JP2015131999A - Dephosphorization method of molten iron - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dephosphorization method of molten iron capable of accurately estimating FeO concentration in a slag during blowing and accurately regulating phosphorus concentration to desired one by using the estimated FeO concentration in the slag, in dephosphorization of molten iron using a converter.SOLUTION: There is provided a dephosphorization method of molten iron including a data collection step of collecting operational data of blowing for molten iron dephosphorization including molten iron condition data and auxiliary raw material data, an ignition point reaction calculation step of calculating an ignition point reaction by using exhaust gas component data and exhaust gas flow rate data of exhaust gas emitted from a converter and the operational data of blowing for molten iron dephosphorization collected in the data collection step, and a slag-metal interface reaction calculation step of sequentially estimating FeO concentration in a slag during blowing by performing a calculation of slag-metal interface reaction using the data calculated in the ignition point reaction step, when dephosphorizing the molten iron in blowing for molten iron dephosphorization using the converter.

Description

  The present invention relates to a hot metal dephosphorization method for controlling the phosphorus concentration in hot metal dephosphorization using a converter.

  Control of phosphorus concentration in the refining process is very important for quality control of steel. In particular, in hot metal dephosphorization blowing, which is the main dephosphorization process, in order to control the phosphorus concentration, the amount of blown oxygen, the amount of auxiliary materials such as quick lime and scale, the top blowing lance height, the top blowing oxygen flow rate, The bottom blowing gas flow rate or the like is used as the operation amount. These operation amounts are often determined by information obtained before the start of blowing, such as target phosphorus concentration, hot metal information, and operation standards created based on past operation results.

  However, even under similar operating conditions, the reproducibility of dephosphorization behavior in actual blowing is not so good. Therefore, in hot metal dephosphorization blowing by the operation amount determined based only on the information obtained before the start of blowing as described above, there has been a problem that variation in phosphorus concentration becomes large.

  In order to deal with the above problem, first, a technique that utilizes measured values of exhaust gas components and exhaust gas flow rate obtained at regular intervals during blowing has been proposed. In Patent Document 1, the amount of FeO produced in the converter is based on the accumulated oxygen amount obtained by sequentially calculating the oxygen balance from the exhaust gas composition and flow rate during blowing, the oxygen gas flow rate, the amount of auxiliary raw material input, and the hot metal component. And adjusting the at least one of the top blowing lance height, oxygen gas flow rate, and bottom blowing gas flow rate according to the estimated FeO amount to reduce the phosphorus concentration after treatment. A method for melting high carbon ultra-low phosphorus steel is disclosed.

  Further, as a technique focusing on the fact that the behavior of the FeO content in the slag during blowing has a great influence on the dephosphorization reaction, Patent Document 2 discloses that the FeO content in the slag during blowing is 30 mass% or more. A hot metal dephosphorization method is disclosed in which the stirring gas flow rate from the bottom blowing tuyere is increased to enhance the slag-metal stirring.

JP 2006-206930 A Japanese Patent No. 4779388

  Formula (1) shows the dephosphorization reaction formula. In the following, “(substance X)” indicates the substance X in the slag, and “[substance Y]” indicates the substance Y in the hot metal. As shown in the formula (1), in order to promote the dephosphorization reaction, it is necessary to increase the CaO concentration in the slag and the FeO concentration in the slag. The methods disclosed in Patent Document 1 and Patent Document 2 are both methods that focus on (FeO) on the left side of the dephosphorization reaction formula.

And when evaluating said dephosphorization reaction rate, the FeO density | concentration [mass% or mol%] in slag which is a relative value is used.

  Patent Document 1 proposes a method of adjusting various operation amounts based on the absolute value of FeO generation amount [kg] in the converter. However, in actual hot metal dephosphorization, since the initial hot metal Si component and the amount of quick lime (CaO) change for each charge, the amount of slag differs for each charge. Even during blowing with the same charge, the amount of slag changes every moment due to the progress of the desiliconization reaction. Even if the amount of FeO produced is the same [kg], the concentration of FeO in the slag is different if the amount of slag is different. From the above, there is a possibility that the operation amount cannot be appropriately adjusted by the method of Patent Document 1 based on the FeO generation amount [kg] in the converter, and the high carbon extremely low phosphorus steel solution based on the method of Patent Document 1 is not possible. The question remains in the realization of the product.

  On the other hand, in patent document 2, the FeO density | concentration (30 mass%) in slag is used as a reference | standard of operation of bottom blowing gas flow rate. However, Patent Document 2 does not describe a specific method for calculating the FeO concentration in the slag during blowing.

  Therefore, the present invention accurately estimates the FeO concentration in the slag during blowing during hot metal dephosphorization using a converter, and uses the estimated FeO concentration in the slag to accurately target the phosphorus concentration to the target phosphorus concentration. It is an object of the present invention to provide a hot metal dephosphorization method that can be used.

In general, the dephosphorization reaction shown in Equation (1) occurs at the slag metal interface, and a model (competitive reaction model) expressing this slag metal interface reaction is “S.Ohguchi et.al: 'Simultaneous dephosphorisation and iron ', Ironmaking and Steelmaking, 11 (1984), p. 41 "(hereinafter, this document may be referred to as" non-patent document "). However, this model focuses only on the slag metal interface reaction and does not take into account the hot spot reaction. Therefore, it cannot be directly applied to hot metal dephosphorization blowing using a converter. Therefore, the present inventors have integrated a calculation process expressing (SiO ₂ ) generation and (FeO) generation in a hot spot reaction and a calculation process expressing a slag metal interface reaction based on a competitive reaction model. Thus, it has been found that the FeO concentration in the slag during blowing can be accurately estimated by sequentially estimating the FeO concentration in the slag during blowing. Furthermore, it has been found that by utilizing the exhaust gas information, it is possible to improve the prediction accuracy of (FeO) generation in the hot spot reaction. The present invention has been completed based on such findings. The present invention will be described below.

  The present invention is a method for dephosphorizing hot metal in hot metal dephosphorization blowing using a converter, and is a data collection for collecting operation data of hot metal dephosphorization blowing including hot metal condition data and auxiliary raw material data The hot spot reaction calculation that calculates the hot spot reaction using the process, exhaust gas component data and exhaust gas flow rate data of the exhaust gas discharged from the converter, and operation data of hot metal dephosphorization blowing collected in the data collection process And a slag metal interface reaction calculation step of sequentially estimating the FeO concentration in the slag during blowing by performing a calculation of the slag metal interface reaction using the data calculated in the hot spot reaction step, Hot metal dephosphorization method.

Here, in the present invention, “data of hot metal conditions” refers to data relating to hot metal used for hot metal dephosphorization blowing. Specifically, for example, hot metal weight, hot metal components (C, Si, Mn, P)), hot metal temperature, hot metal ratio, and the like.
In the following description of the present invention, “%” relating to concentration is used in the meaning of “mass%” unless otherwise specified.

  In the present invention, the hot metal Si concentration other than the hot spot region is estimated in the slag metal interface reaction calculation step, and the FeO concentration in the slag at the time when the estimated hot metal Si concentration reaches 0.02%. In the case of 20% or less, it is preferable to have a dephosphorization promoting treatment step of performing any one selected from the group consisting of a decrease in acid feed rate, an increase in lance height, and an addition of an oxygen-containing auxiliary material. .

  Further, in the present invention, when the FeO concentration in the slag estimated in the slag metal interface reaction calculation step is 50% or more, it consists of an increase in the acid feed rate, a decrease in the lance height, and the introduction of a sedative. It is preferable to have a slopping suppression processing step for performing any one selected from the group.

  According to the present invention, in hot metal dephosphorization using a converter, the FeO concentration in the slag during blowing is accurately estimated, and the phosphorus concentration is accurately adjusted to the target phosphorus concentration using the estimated FeO concentration in the slag. It is possible to provide a hot metal dephosphorization method that can be used.

It is a flowchart explaining one Embodiment of the hot metal dephosphorization method of this invention. It is a figure explaining the outline | summary of the example of an estimation method of the FeO density | concentration in slag in this invention. It is a figure explaining the system configuration example which can implement the hot metal dephosphorization method of this invention. It is a figure which shows the estimation result (calculated value) and measured value of phosphorus concentration in an Example. It is a figure which shows the estimation result (calculated value) and measured value of FeO density | concentration in slag in an Example. It is a figure which shows the estimation result (calculated value) and measured value of the phosphorus concentration in a comparative example. It is a figure which shows the estimation result (calculated value) and actual value of the FeO density | concentration in slag in a comparative example.

  Embodiments of the present invention will be described below. In addition, the following description is an illustration of this invention and this invention is not limited to the form demonstrated below.

  FIG. 1 is a flowchart for explaining an embodiment of the hot metal dephosphorization method of the present invention. In the present invention shown in FIG. 1, the data collection step (STEP 1), the fire point reaction calculation step (STEP 2), the slag metal interface reaction calculation step (STEP 3), and whether the FeO concentration in the slag is 20% or less. Step (STEP4), dephosphorization promoting treatment step (STEP5), step of judging whether or not the FeO concentration in the slag is 50% or more (STEP6), and the stepping suppression treatment step (STEP7) And a step (STEP 8) for determining whether or not the blowing has been completed.

<Data collection process (STEP 1)>
The data collection step (STEP 1) is a step of collecting operation data of hot metal dephosphorization blowing including hot metal condition data and auxiliary raw material data. The data of the hot metal conditions collected in STEP 1 are hot metal weight, hot metal components (C, Si, Mn, P, etc.), hot metal temperature, and hot metal ratio. In addition, the auxiliary raw material data collected in STEP 1 includes the components and weight of the auxiliary raw material that are put into the converter during hot metal dephosphorization blowing.

<Firepoint reaction calculation step (STEP 2)>
The hot spot reaction calculation step (STEP 2) calculates the hot spot reaction using the component and flow rate data of the exhaust gas discharged from the converter and the operation data of hot metal dephosphorization blowing collected in STEP 1. It is a process to be performed. In the present invention shown in FIG. 1, the FeO concentration in slag during hot metal dephosphorization blowing using a converter (hereinafter referred to simply as “slag”) is calculated by a slag metal interface reaction calculation step (STEP 3) described later using the result of STEP 2. It is sometimes referred to as “medium FeO concentration”).

  FIG. 2 shows an outline of an example of a method for estimating the FeO concentration in slag in the present invention. As illustrated in FIG. 2, in the present invention, when estimating the FeO concentration in the slag, a calculation process that handles a fire point reaction and a calculation process that handles a slag metal interface reaction based on a competitive reaction model are performed. In the present invention shown in FIG. 1, the calculation process that handles the hot spot reaction corresponds to STEP2, and the calculation process that handles the slag metal interface reaction based on the competitive reaction model corresponds to STEP3 described later.

  The fire point reaction handled in STEP 2 will be described. At the fire point, it is assumed that an oxidation reaction of [Si], [C], and [Fe] occurs as a reaction of the metal-containing component. And the mass balance of each metal containing component is represented like Formula (2)-(4).

Here, [Si] _f , [C] _f , and [Fe] _f are metal-containing components [%], [Si], [C], and [Fe] in the hot spot region. Metal-containing component [%], k _Si is desiliconization reaction rate constant [% / s], ΔC is decarburization rate obtained from exhaust gas information [% / s], ΔFe is iron oxidation rate obtained from exhaust gas information [% / S], V _f is the metal volume [m ³ ] in the hot spot region, and Q is the reflux amount [m ³ / s].

  The decarburization rate (ΔC) obtained from the exhaust gas information is calculated from the equation (5) using the measurement data of the exhaust gas flow rate and the exhaust gas component.

Where Q _offgas is the exhaust gas flow rate [m ³ / h (NTP)], CO is the CO concentration in exhaust gas [%], CO ₂ is the CO ₂ concentration in exhaust gas [%], and W _f is the weight of the hot spot region. [Ton].

The iron oxidation rate (ΔFe) determined from the exhaust gas information is obtained by subtracting oxygen consumed for decarburization and desiliconization reactions from oxygen (FO ₂ ) supplied from outside the furnace into the furnace, It represents with Formula (6).

Here, FO ₂ is in-furnace supply oxygen [m ³ / h (NTP)].

Furthermore, the production rate of (SiO ₂ ) and the production rate of (FeO) at the above-mentioned fire point are expressed by Equation (7) and Equation (8), respectively, using Equation (2) and Equation (4).

Here, a _{(SiO 2) f} and _{(FeO) f} slag containing component generated by the fire spot area [%], _{W S} is the slag weight [ton].

  In addition, the heat balance equation in the hot spot region is expressed as the following equation (9) in consideration of each reaction heat generated in the hot spot reaction.

Here, c _pf is the specific heat in the hot spot region [kcal / (kg · ° C.)], H _{reac, f} is the heat of reaction in the hot spot region [kcal / s], RQ is the heat inflow due to reflux [kcal / s], RQ _f is the heat outflow [kcal / s] due to reflux.

With the above formulation, the behavior of the metal-containing component due to the oxidation reaction at the fire point and the behavior of the oxides ((SiO ₂ ) and (FeO)) supplied to the slag can be expressed. In STEP2, the above formulas (2) to (9) are calculated.

<Slag metal interface reaction calculation step (STEP 3)>
The slag metal interface reaction calculation step (STEP 3) is a step of sequentially estimating the FeO concentration in the slag during blowing by calculating the slag metal interface reaction using the data calculated in STEP 2. The slag metal interface reaction handled in STEP 3 will be described below.

It is considered that the reaction at the slag metal interface is caused by mass transfer using the difference between the slag metal interface concentration and the metal bulk concentration as a driving force. The mass balance equation of the metal-containing component i ([X _i ]) is represented by the formula (10).

Here, [X _i ] is a metal bulk component i [%], and [X _i ] = {[C], [Si], [Mn], [P], [Fe]}. Here, the “metal bulk” represents a region other than the hot spot region, and the hot metal Si concentration other than the hot spot region is calculated from the equation (10). [X _i ^* ] is the equilibrium concentration [%] of component i at the slag metal interface, V is the metal volume [m ³ ] other than the hot spot region, A is the area [m ² ] of the slag metal interface, K _i Is the mass transfer coefficient [m / s] of the component i, [X _{i, f} ] is the concentration [%] of the component i in the hot spot region, and WX _{i, SUB} considers the increase of the component i due to the input of the auxiliary material Is the input term [% / s] of the contained component i.

As described in the above non-patent document, the equilibrium concentration ([X _i ^* ]) of the component i contained at the slag metal interface of the formula (10) is represented by using the interface oxygen concentration ao ^* . The interface oxygen concentration ao ^* is calculated from an oxygen balance equation at the slag metal interface.

  At this time, the mass balance of the slag component can also be expressed as in equation (11) based on the mass transfer rate-determining method, similarly to the metal-containing component.

Here, (XO _j ) is the concentration [%] of the slag-containing component j, and (XO _j ) = {(CaO), (SiO ₂ ), (FeO), (MgO), (P ₂ S ₅ ), (Al ₂ O ₃ )}. Further, _(XO ^{j *)} is the equilibrium concentration of the slag containing component j in the slag metal interface [%], _{V S} is the slag volume ^[m 3], the mass transfer coefficient _{K j} is the slag containing component j [m / s], WXO _{j, SUB} is an input term [% / s] of the slag-containing component j in consideration of an increase in the slag-containing component j due to the input of the auxiliary material.

However, regarding (SiO ₂ ), it is represented by the formula (12) in which the production rate of (SiO ₂ ) in the fire point reaction represented by the above formula (7) is added to the last term on the right side, and regarding (FeO), This is expressed by Equation (13) in which the rate of formation of (FeO) in the hot spot reaction represented by Equation (8) is added to the last term on the right side. By this treatment, it is possible to represent a phenomenon in which (SiO ₂ ) and (FeO) generated by the hot spot reaction flow into the slag region.

  Next, the heat balance equations in the metal region and the slag region constituting the slag metal interface reaction are expressed by equations (14) and (15), respectively.

Here, W is the weight outside the hot spot region [ton], cp is the specific heat outside the hot spot region [kcal / (kg · ° C.)], H _reac is the heat of reaction at the slag metal interface [kcal / s], RQ _f 'Is the heat inflow [kcal / s] from the hot spot region to the region other than the hot spot region, RQ' is the heat outflow [kcal / s] from the region other than the hot spot region, and Q _SUB is the auxiliary material The amount of heat removed by melting [kcal / s].

Here, cp _S is the specific heat of the slag region [kcal / (kg · ° C.)], H _{reac, S} is the reaction heat of the slag metal interface [kcal / s], and RQ _f is the amount of heat _removed from the slag surface [kcal / s. ].

In STEP3, the above formulas (10) to (15) are calculated.
By STEP2 and STEP3 in which the above formulas (2) to (15) are calculated, the (FeO) concentration in the slag during blowing can be sequentially estimated.

<Step of determining whether or not the FeO concentration in the slag is 20% or less (STEP 4)>
In the step of determining whether or not the FeO concentration in the slag is 20% or less (STEP 4), the hot metal Si concentration estimated value other than the hot spot region estimated in STEP 3 reaches 0.02%. This is a step of determining whether or not the (FeO) concentration is 20% or less. When an affirmative determination is made in STEP 4 (when the (FeO) concentration in the slag is 20% or less), the process is sent to STEP 5. On the other hand, when a negative determination is made in STEP 4 (when the concentration in the slag (FeO) is higher than 20%), the processing is sent to STEP 6.

<Dephosphorization promoting treatment step (STEP 5)>
In the dephosphorization promoting treatment step (STEP 5), when an affirmative determination is made in STEP 4, that is, when the hot metal Si concentration estimated value other than the hot spot region estimated in STEP 3 reaches 0.02% ( A step of performing any one (1 or more) selected from the group consisting of a decrease in acid delivery rate, an increase in lance height, and an addition of an oxygen-containing auxiliary material when the FeO) concentration is 20% or less It is.
In other words, STEP5 is a process performed for the purpose of improving the accuracy of the target phosphorus concentration using the slag (FeO) concentration estimated in STEP3.

  As a result of investigations of past operation data by the present inventors, it has been found that keeping the slag (FeO) concentration at the high level in the initial stage of blowing is effective for low-level stable dephosphorization. When the estimated molten iron concentration outside the hot spot region reaches 0.02%, the estimated value in slag (FeO) is as low as 20% or less, depending on the target phosphorus concentration. By performing the operation shown in FIG. 1, the phosphorus concentration can be controlled with high accuracy to a target phosphorus concentration or less.

<Step of determining whether the FeO concentration in the slag is 50% or more (STEP 6)>
The step of determining whether or not the FeO concentration in the slag is 50% or more (STEP 6) is a step of determining whether or not the (FeO) concentration in the slag estimated in STEP 3 is 50% or more. If an affirmative determination is made in STEP 6 (when the (FeO) concentration in the slag estimated in STEP 3 is 50% or more), the process proceeds to STEP 7. On the other hand, when a negative determination is made in STEP 6 (when the (FeO) concentration in the slag estimated in STEP 3 is less than 50%), the process proceeds to STEP 8.

<Sloping Suppression Treatment Step (STEP 7)>
When the affirmative determination is made in STEP 6, that is, when the concentration in the slag (FeO) estimated in STEP 3 is 50% or more, the slopping suppression treatment step (STEP 7) It is a step of performing any one (1 or 2 or more) selected from the group consisting of descent and sedative injection.

  In hot metal dephosphorization blow smelting using an actual converter, it is desirable to suppress the slopping of the slag in the furnace to the outside of the furnace. When large slopping occurs, it may cause a decrease in productivity such as emergency stop. One of the causes of slopping is generally a high slag (FeO) concentration. Therefore, in STEP7, when the estimated value in the slag (FeO) concentration during blowing estimated in STEP3 is 50% or more, the operation shown in Table 2 is performed. As a result, the estimated value of slag (FeO) concentration can be kept lower than 50%, and as a result, slopping can be suppressed.

<Step of determining whether or not blowing has been completed (STEP 8)>
In the step of determining whether or not the blowing is finished (STEP 8), it is determined whether or not the blowing is finished. When a negative determination is made in STEP 8 (when blowing is not completed), the process returns to STEP 2 and the processes of STEP 2 to STEP 8 are repeated until an affirmative determination is made in STEP 8. On the other hand, when a positive determination is made in STEP 8 (when blowing is finished), the calculation is finished.

  According to the present invention of the above form, the hot metal dephosphorization blowing using a converter estimates the (FeO) concentration in slag with high accuracy, and based on this estimated value, the acid feed rate and lance height during blowing By adjusting etc., it is possible to accurately target the phosphorus concentration to the target value while suppressing slopping.

FIG. 3 is a diagram illustrating a configuration example of a hot metal dephosphorization system capable of performing the hot metal dephosphorization method of the present invention. In the hot metal dephosphorization system 10 shown in FIG. 3, the hot metal / sub-material data 1 includes hot metal conditions such as the hot metal weight for each charge, hot metal components (C, Si, Mn, P, etc.), hot metal temperature, hot metal ratio, etc. This is the data on the auxiliary materials, etc. that were input during smelting. Parameter 2 sets parameters for the desiliconization rate constant and mass transfer coefficient. The target data 3 is data of a target phosphorus concentration in hot metal dephosphorization for each charge. In the hot spot reaction calculation unit 4, the above STEP2 is performed. Specifically, by using exhaust gas information (exhaust gas flow rate, exhaust gas component), estimation calculation of [C], [Si], [Fe] at the fire point based on the formulas (2) to (9), and (SiO ₂ ) The production rate of (Fe) and the production rate of (FeO) are calculated. In the slag metal interface reaction calculation unit 5, the above STEP3 is performed. Specifically, the slag metal based on the competitive reaction model using the (SiO ₂ ) generation rate and the (FeO) generation rate calculated by the fire point reaction calculation unit 4 based on the equations (10) to (15). By calculating to express the interfacial reaction, the (FeO) concentration in slag is estimated. Furthermore, the hot metal Si concentration other than the hot spot region is estimated by the equation (10) representing the change of the content component in the metal bulk which is the region other than the hot spot region. Further, in the dephosphorization promoting processing calculation unit 6, the above STEP5 is performed. Specifically, based on the slag (FeO) concentration calculated by the slag metal interface reaction calculation unit 5, for example, the operation determined according to Table 1 is performed. Further, the step 7 is performed in the slapping suppression processing calculation unit 7. Specifically, based on the slag (FeO) concentration calculated by the slag metal interface reaction calculation unit 5, for example, the operation determined according to Table 2 is performed. The calculation results of the slag metal interface reaction calculation unit 5, the dephosphorization promotion processing calculation unit 6, and the slopping suppression processing calculation unit 7 are displayed on the input / output unit 8. By using the hot metal dephosphorization system 10 configured as described above, the FeO concentration in the slag during hot metal dephosphorization blowing using the converter is accurately estimated, and the estimated FeO concentration in the slag is used to determine the phosphorus concentration. Can be accurately targeted at the target phosphorus concentration.

  In the above description of the present invention, the embodiment having the dephosphorization promoting treatment step (STEP 5) and the slopping suppression treatment step (STEP 7) has been exemplified, but the present invention is not limited to this embodiment. The present invention can be configured not to have a dephosphorization promoting treatment step or a slopping suppression treatment step, and can also be configured to have neither a dephosphorization promoting treatment step or a slopping suppression treatment step. It is. However, it is preferable that the present invention has a form having a dephosphorization promoting process from the viewpoint of easily improving the accuracy of the target phosphorus concentration. Moreover, it is preferable to set it as the form which has a slopping suppression process process from a viewpoint made into the form which is easy to suppress slopping.

  Hot metal dephosphorization blowing was performed while adding the auxiliary materials shown in Table 4 to the hot metal indicated in Table 3. During this hot metal dephosphorization, using the hot metal dephosphorization method of the present invention (Example) and the conventional competitive reaction model (comparative example) that does not take into account the hot spot reaction, the FeO concentration in the slag and phosphorus Concentration was estimated. FIG. 4A shows the estimation result (calculated value) and actual measurement value of the phosphorus concentration in the example, FIG. 4B shows the estimation result (calculated value) and actual measurement value of the FeO concentration in the slag in the example, and the estimation result of phosphorus concentration in the comparative example. FIG. 5A shows the (calculated value) and the actually measured value, and FIG. 5B shows the estimation result (calculated value) and the actually measured value of the FeO concentration in the slag in the comparative example.

As shown in FIGS. 4B and 5B, in the example, the FeO concentration in the slag could be estimated with higher accuracy than in the comparative example. As a result, as shown in FIGS. 4A and 5A, in the example, the phosphorus concentration could be estimated with higher accuracy than in the comparative example.
From the above, according to the present invention, it is possible to accurately estimate the FeO concentration in the slag during blowing, so that the phosphorus concentration is accurately targeted to the target phosphorus concentration using the estimated FeO concentration in the slag. Was found to be possible.

DESCRIPTION OF SYMBOLS 1 ... Hot metal / subsidiary raw material data 2 ... Parameter 3 ... Target data 4 ... Fire point reaction calculating part 5 ... Slag metal interface reaction calculating part 6 ... Dephosphorization promotion processing calculating part 7 ... Slopping suppression processing calculating part 8 ... Input / output part 10 ... Hot metal dephosphorization system

Claims (3)

A method for dephosphorizing hot metal in hot metal dephosphorization blowing using a converter,
A data collection process for collecting hot metal dephosphorization blowing operation data including hot metal condition data and auxiliary raw material data;
The hot spot reaction is calculated using the exhaust gas component data and the exhaust gas flow rate data of the exhaust gas discharged from the converter, and the hot metal dephosphorization operation data collected in the data collection step. A calculation process;
A slag metal interface reaction calculation step of sequentially estimating the FeO concentration in the slag during blowing by calculating the slag metal interface reaction using the data calculated in the fire point reaction step,
A hot metal dephosphorization method. When the molten iron Si concentration other than the hot spot region is estimated in the slag metal interface reaction calculation step, and when the estimated molten iron Si concentration reaches 0.02%, the FeO concentration in the slag is 20% or less, The hot metal dephosphorization process according to claim 1, further comprising a dephosphorization promoting treatment step for performing any one selected from the group consisting of a decrease in acid feed rate, an increase in lance height, and an addition of an oxygen-containing auxiliary material. Method. When the FeO concentration in the slag estimated in the slag metal interface reaction calculation step is 50% or more, it was selected from the group consisting of an increase in acid delivery rate, a decrease in lance height, and a sedative injection The hot metal dephosphorization method according to claim 1, wherein the hot metal dephosphorization method has a slopping suppression treatment step.