JP4807895B2 - Converter main raw material blending method - Google Patents

Description

【００３０】
【発明の効果】
以上述べたところから明らかなように、本発明によれば、転炉出鋼量を精度よく推定計算でき、かつ転炉出鋼温度を精度よく推定計算して転炉での主原料配合が適切にできる。従って、炭素質あるいはFeSiといった高価な昇熱材を使用することなしに、あるいは、鉄鉱石やスケールなどの冷却材を多量投入することなく吹錬が可能である。また、鉄収支および熱収支を学習させることにより転炉炉容積の変化などの経時変化に対応できる。
【００３１】
さらには、コストメリットの高いMn成分規格の高い鋼種に積極的に熱余裕を持たせ、炭素質あるいはFeSiといった高価な昇熱材を使用することなしに、あるいは、鉄鉱石やスケールなどの冷却材を多量投入してMn歩留りを低減させることなく、Mn鉱石使用量の拡大を図ることができる。
【００３２】
以上の結果、主原料配合段階で種々の条件変化に対して各計算モデルを有機的に結合して主原料配合量の計算を行い、これに基づいて主原料配合計を行うことにより、エネルギーミニマムの転炉吹錬が実施可能となる。
【図面の簡単な説明】
【図１】 転炉の主原料配合量を計算機で制御する計算機設備例を示す図である。
【図２】 本発明に関わる主原料配合量計算の手順を説明する図である。
【図３】 図２に示す１〜６の個別の計算を主原料配合量計算の一部として使用する場合の参考例を示す図である。
【図４】 本発明に関わる主原料配合量計算において脱りん処理計算を追加した主原料配合量計算の手順を説明する図である。
【図５】 比較例である従来の計算モデルによる主原料配合計算における熱余裕の実績値を示す図である。
【図６】 実施例である本発明に関わる計算モデルによる主原料配合計算における熱余裕の実績値を示す図である。
【符号の説明】
１…吹止［Ｃ］予測計算、２…出鋼温度予測計算、３…転炉副原料投入量計算、４…合金鉄投入量計算、５…転炉鉄収支計算、６…転炉熱収支計算、７…主原料配合計算、８…脱りん処理計算。[0001]
BACKGROUND OF THE INVENTION
In the present invention, when a pre-treated hot metal is charged into an upper-bottom-blown converter and decarburization and / or dephosphorization is performed, a blending calculation of main raw materials such as hot metal, scrap, and cold iron is performed using a computer. It belongs to the technical field of the method of using and controlling accurately.
[0002]
[Prior art]
When calculating the raw material composition, the composition and temperature of the molten iron in the furnace, the temperature, the secondary auxiliary material input brand and input amount, the iron alloy input brand and input amount at the time of converter steelmaking, the steel output temperature, the blowout [C Among the values that are the preconditions for calculating the heat balance and the iron balance of the main raw material composition, the actual value is used for the value that has already been confirmed in the main raw material composition stage. However, since the main raw material blending needs to be performed before the actual treatment (blowing), it may be necessary to change the target components and temperature after the treatment. Therefore, conventionally, the main raw material blending calculation is performed in the main raw material blending calculation using the set value determined in advance for each steel type as the set value of the precondition.
[0004]
In addition, as seen in JP-A-5-33029 and the like, the main raw material blending calculation is considered to have a main purpose of securing the amount of steel output by “iron balance”. did not have to adjust the main raw material amount in view of the "heat balance" is an important operating factor influencing refining properties.
[0005]
In the case of dephosphorization in advance in the hot metal stage before the charging of the converter, the dephosphorization reaction is performed at a temperature as low as possible compared to 1600 to 1750 ° C. in the converter. The subsequent temperature is generally processed in the range of 1250 to 1350 ° C. in consideration of the solidification temperature of the hot metal. This temperature is about 50 ° C. lower than 1300 to 1400 ° C., which is the hot metal temperature when charging the converter without dephosphorization. In addition, since the dephosphorization treatment is oxidation refining, decarburization and desiliconization reactions occur simultaneously with the dephosphorization reaction, and the [C] concentration in the hot metal is from 4.3 to 4.8 % by mass at the time of blast furnace discharge. When decarburized by about 0.3 to 1.0 % by mass and charged in the converter, it falls to the range of 3.5 to 4.4 % by mass , and the [Si] concentration in the hot metal is also 0. It will fall to about 0.10 mass% or less from 2-0.6 mass% . Similarly, the [P] concentration in the hot metal also decreases from 0.07 to 0.15 mass% at the time of blast furnace discharge to a range of 0.005 to 0.050 mass% . These [C] [Si] [P] components generate heat by the oxidation reaction and work to raise the hot metal temperature. However, by carrying out the dephosphorization process in the hot metal stage before charging the converter, the heat of reaction is reduced. It decreases in the converter stage, and the thermal margin in the converter stage is remarkably reduced together with the decrease in the converter charging temperature. For this reason, in this invention, converter charging temperature is 1250-1350 degreeC, [C]: 3.5-4.5 mass% , [Si]: 0.10 mass% or less, [P]: 0.005- The hot metal subjected to dephosphorization treatment of 0.050 % by mass was used as a target.
[0006]
Therefore, if the dephosphorization process is performed in advance in the hot metal stage before the converter charging, there is no thermal margin. It is necessary to use a new heat-up material. When these heat-up materials are used, further, if carbon is used, the blowing time is extended, resulting in a decrease in productivity and an increase in heat dissipation, resulting in a decrease in energy efficiency. In addition, when FeSi is used, it is necessary to use an increased amount of CaO source such as quick lime to adjust the basicity, resulting in an increase in the amount of slag generated, resulting in an increase in heat loss, iron yield and Mn yield decreases.
[0007]
On the other hand, if the heat margin is too large, it is sufficient to increase the amount of iron ore / scale and other coolants. However, when the converter is blown using hot metal that has undergone hot metal pretreatment, Because the amount of slag in the furnace is small, the iron oxide concentration (% T.Fe) in the furnace slag will increase excessively when a large amount of iron oxide such as iron ore and scale is used. . As a result, a decrease in iron yield and Mn yield, and an increase in the slag amount, an increase in the rate of erosion of the converter refractory, leading to a decrease in converter furnace life.
[0008]
Furthermore, when the iron yield changes in this way, the increase or decrease also occurs with respect to the target steel output. If the amount of steel output is small, energy efficiency decreases due to a decrease in tonnage per charge, and in extreme cases, it may become impossible to output steel due to restrictions on the freeboard (space height) of the ladle and restrictions on molten steel processing. Conversely, if the amount of steel output is large, the hoisting machine cannot be lifted and conveyed.
[0009]
However, in the above technology, since the main raw material composition calculation is performed using the value set for each steel type, the error due to the value is large, and as a result, the accuracy of the main raw material composition calculation is low. The above challenges remain. In addition, since the estimation calculation accuracy of each precondition value is low, it has been determined that the accuracy is improved by using a constant, and so far, the constant has been used.
[0010]
In particular, in the case of continuous and efficient production from the pretreatment to the converter production process, hot metal, one of the main raw materials, is being pretreated or after the treatment, before the components and temperature are known. The need to carry out the main raw material formulation occurs quite often. Furthermore, even if there is a time allowance, the sample / temperature measurement after processing becomes impossible, and the analysis value / temperature measurement value may not be known. In such a case, if the calculation accuracy of the components and temperatures charged to the converter is low, the blending balance of the main raw materials actually charged to the converter will deviate from the calculation and become inappropriate, resulting in energy loss and steel output. The amount will deviate from the target value.
[0011]
The target steel output temperature varies depending on the molten steel processing after the converter and the continuous casting process, waiting time, pan conditions, etc. Therefore, it is necessary to accurately estimate and calculate the optimum target temperature. If the target steel output temperature changes, the dephosphorization efficiency and Mn yield in the converter will be greatly affected, so the optimum secondary material input will change and the heat balance and iron balance will change. I can't consider changes.
[0012]
When converter blowing is performed using hot metal that has been subjected to hot metal pretreatment, the dephosphorization processing load in the converter is reduced, so that the amount of slag in the converter can be reduced. Therefore, since it is possible to improve the yield of Mn in the converter, it is general to actively use Mn ore in the converter for the purpose of suppressing the amount of expensive Mn-based alloy iron used. However, in the conventional calculation of the main raw material, Mn ore is not taken into account, and when the hot metal is actually charged into the converter, if there is a heat margin in the converter, Mn ore If there is no heat margin, an expensive heat-up material such as carbonaceous or FeSi was used. On the other hand, if there is an excessive heat margin, a large amount of coolant such as iron ore or scale is added (% T.Fe) to increase (Mn yield).
[0013]
The present invention has been made to solve the above problems, and the molten iron temperature is 1250 to 1350 ° C., [C]: 3.5 to 4.5 mass% , [Si]: 0.10 mass. % , [P]: 0.005 to 0.050 mass% , hot-melted dephosphorized iron in the hot metal stage before charging the converter in advance, with an upper bottom blow mold of 70 to 350 t scale in performing charging to decarburization and / or dephosphorization treatment converter, molten iron, scrap, per the control using the computer the blending calculation of the main raw material of Hiyazuku, heat balance iron main raw material formulation To provide a main raw material blending method for a converter that calculates the variables that are the preconditions for calculating the balance by using a calculation model that estimates each of the variables, and blends the main raw material by blending the main raw material. With the goal.
[0014]
[Means for Solving the Problems]
The summary is that the molten iron temperature is 1250 to 1350 ° C., [C]: 3.5 to 4.5 mass% , [Si]: 0.10 mass% or less, [P]: 0.005 to 0.050. The hot metal with no heat margin that has been dephosphorized in advance in the hot metal stage before charging the converter, which is mass% , is charged into a 70-350t scale bottom-bottom converter and decarburized and / or decarburized. in performing phosphorous process, molten pig iron, scrap, per the control using the computer the blending calculation of the main raw material of Hiyazuku, components and temperature of Tenro charging molten iron, the converter secondary feedstock input stocks and input amount, BOF Calculation models that estimate the variables that are the preconditions for calculating the heat balance and iron balance of the main raw material composition, such as the alloy iron input brand and amount, the output temperature, and the blowout [C] Calculated by using the calculation results, and using these calculation results, iron balance calculation and calorific value in the converter Performed supporting calculations, and its iron balance calculations and heat balance calculation, that performs data transmission and reception more than once between the main raw material formulation calculated by the blending calculations accurately Shugenryo blending main raw material This is a method for blending the main raw materials of the converter.
[0017]
After dephosphorization treatment in the top-bottom blown converter, the temperature of 1250 to 1350 ° C., [C]: 3.5 to 4.5 mass% , remaining in the furnace after removing the dephosphorization slag, Si]: 0.10 % by mass or less, [P]: 0.005 to 0.050 % by mass of the hot metal having no heat margin when the decarburization process and / or the dephosphorization process are performed again. This is a method for blending the main raw materials of the furnace.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is premised on control using a computer, and an example will be described based on computer equipment as shown in FIG. “Steam Weighing Station” that delivers the required amount of hot metal to the container charged with hot metal into the converter, “Scrap Weighing Station” that puts the required amount into the container charged with scrap and cold metal into the converter, and main raw materials Installed a “main raw material blending indicator” that indicates the blending amount and a TV that displays the calculation results of the computer in a converter, etc., and applied the blended amount calculated as a result of the present invention to the actual blending to achieve the effects described below. Achieve. In addition, the layout and configuration of the hot metal, scrap, and cold steel weighing stations will vary depending on the operation mode of the steelmaking process, and when blending automatically based on the amount of blending calculation related to the invention, when mechanical blending is performed automatically In addition, an example is conceivable in which the operator performs the blending by manually operating the mechanical equipment based on the blending calculation amount.
[0019]
Then, the method to calculate a compounding quantity is demonstrated. The method for calculating the amount is calculated based on the concept shown in FIG. In the blow stop [C] prediction calculation 1, first, the blow stop [C] is determined, and using this blow stop [C], the steel output temperature is calculated in the next steel output temperature prediction calculation 2. Using the blow-off [C] and the output steel temperature, calculate the input amount of the auxiliary material in the converter auxiliary material input calculation 3, and use the blow-off [C], the output steel temperature, and the auxiliary material input. Then, the alloy iron input amount is calculated by the alloy iron input amount calculation 4, and finally, all of the results of these respective calculations are used to calculate the converter iron balance calculation 5 and the converter heat balance calculation 6, The blending calculation of the main raw material is performed accurately by sending and receiving data to and from the blending calculation 7 at least once. In addition, a case where the calculation from the first calculation described in 1 to the last calculation described in 7 is repeated a plurality of times or the calculation is completed only once is included.
[0020]
Next, calculation of each calculation executed in FIG. 2 using actual data such as the actual blending amount of single or multiple charges already blown in the converter and the temperature and composition at the time of steelmaking from the converter . The coefficient is changed and learned so that the error between all the actual data and the corresponding calculation result is as small as possible, so that the accuracy is maintained or improved corresponding to the change with time.
[0021]
Necessary or sufficient to calculate the amount of Mn ore input to the converter or the amount of iron Mn ore appropriate or sufficient to meet the Mn standard required for the charge by any of the calculations 1 to 3 etc. The blending amount of the main raw material is calculated so that there is sufficient heat margin. At this time, based on the blowout [Mn] predicted from the amount of Mn ore input to the converter or the amount of iron Mn ore, the amount of alloy iron related to Mn should be accurately calculated in the calculation of the amount of alloy iron input in 4 Thus, the accuracy of the main ingredient blending amount is also improved.
[0022]
In the above description, when decarburization treatment and / or dephosphorization treatment is performed in a series of treatments, after dephosphorization treatment, once decarburized and again decarburization treatment and / or dephosphorization treatment is performed. 2 or FIG. 3, it is possible to calculate the main raw material blending amount with high accuracy by considering the waste after the dephosphorization process in each calculation of FIG. In addition, the dephosphorization process before and after excretion includes a case where independent calculation is performed in the form of dephosphorization process calculation 8 as shown in FIG.
[0023]
As described above, the present invention determines the blowout [C] in the blowout [C] prediction calculation as well as the main raw material blending calculation model , and uses this blowout [C] to predict the steel output temperature. Calculate the steel output temperature in the calculation, and further use the blowout [C] and the steel output temperature to calculate the input amount of the secondary raw material in the converter secondary raw material input amount calculation, the blowout [C], Using the steel output temperature and auxiliary raw material input amount, the iron alloy input amount is calculated by calculation of the iron alloy input amount, and the iron balance calculation and calorie balance calculation in the converter are performed using these calculation results. Therefore, it is possible to accurately calculate the amount of steel output and the temperature of steel output at the time of steel output from the converter. That is, by using the main raw material blending method of the present invention, the converter steel output temperature can be accurately estimated and calculated, and the main raw material blend of the converter can be made appropriate. Therefore, blowing can be performed without using an expensive heat increasing material such as carbonaceous material or FeSi or without adding a large amount of coolant such as iron ore or scale.
[0024]
As a result, it is possible to suppress a decrease in energy efficiency without causing a decrease in productivity and an increase in heat dissipation due to the extension of the blowing time. In addition, it is not necessary to use an increased amount of CaO source such as quick lime for adjusting the basicity, and heat loss is not increased, and further, iron yield and Mn yield are not reduced. Also, the iron oxide concentration (% T.Fe) in the furnace slag does not increase excessively, resulting in a decrease in iron yield and Mn yield, and an increase in the rate of melting of converter refractories. However, it is possible to suppress a decrease in converter furnace life.
[0025]
Further, by learning the iron balance and the heat balance, it is possible to cope with changes with time such as changes in the converter furnace volume.
[0026]
By applying the above calculation model and optimizing the heat balance in the converter, the steel grades with high cost merit and high Mn component specifications are positively given a thermal margin, and carbonaceous or FeSi is expensive. The amount of Mn ore used can be increased without using a heat material, or without adding a large amount of coolant such as iron ore or scale to reduce the Mn yield.
[0027]
【Example】
Next, an example of actual operation will be described. As a comparative example, blending main raw materials with a conventional computer model in a process in which hot metal that has undergone desiliconization and dephosphorization treatment using a 280-ton mixing car is loaded together with scrap into a 240-ton top-bottom blowing converter. FIG. 5 shows the result of the main raw material blending based on the calculation result, and FIG. 6 shows the result of applying the calculation result of the present invention as an example. These show the heat margin in the converter in terms of hot metal mixing ratio (HMR), and it is sufficient if the target heat margin can be secured with small variations. Here, the target thermal margin is a thermal margin sufficient to input Mn ore corresponding to the Mn standard, and in the examples, the hot metal content was 1.8%. In addition, if phosphorus is not reduced to below the upper limit of phosphorus for crude steel in the dephosphorization process in the pretreatment stage, it is necessary to dephosphorize again in the converter stage. It is necessary to further secure a sufficient heat margin for supplying a coolant such as scale or iron ore necessary for hatching the ironmaking material.
[0028]
When FIG. 5 and FIG. 6 are compared, the variation can be reduced according to the present invention with respect to the target thermal margin (see FIG. 6). As a result, as shown in Table 1, a large amount of Mn ore could be blended, and the amount of iron oxide-based coolants such as scale and iron ore and heat-generating materials such as FeSi and graphite could be reduced.
[0029]
[Table 1]

[0030]
【The invention's effect】
As is apparent from the above description, according to the present invention, the amount of steel output from the converter can be accurately estimated and calculated, and the temperature of the steel output from the converter can be accurately estimated to calculate the main raw material composition in the converter. Can be. Therefore, blowing can be performed without using an expensive heat-up material such as carbonaceous material or FeSi, or without adding a large amount of coolant such as iron ore or scale. In addition, by learning the iron balance and heat balance, it is possible to cope with changes over time such as changes in the converter furnace volume.
[0031]
In addition, the steel grades with high Mn component specifications, which have high cost merit, have positive thermal margins, without using expensive heat-up materials such as carbonaceous or FeSi, or coolants such as iron ore and scales. The amount of Mn ore used can be expanded without increasing the amount of Mn and reducing the yield of Mn.
[0032]
As a result of the above, the energy consumption minimum is obtained by organically combining the calculation models for various conditions at the main raw material blending stage to calculate the main raw material blending amount, and performing the main raw material distribution based on this. It becomes possible to carry out the converter blowing.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of computer equipment for controlling the amount of main raw material of a converter by a computer.
FIG. 2 is a diagram for explaining the procedure for calculating the amount of main raw material according to the present invention.
FIG. 3 is a diagram showing a reference example in a case where the individual calculations 1 to 6 shown in FIG. 2 are used as a part of the main raw material blend amount calculation.
FIG. 4 is a diagram for explaining a main raw material blending amount calculation procedure in which a dephosphorization calculation is added in the main raw material blending amount calculation according to the present invention.
FIG. 5 is a diagram showing an actual value of thermal margin in a main raw material blending calculation by a conventional calculation model as a comparative example.
FIG. 6 is a diagram showing an actual value of heat margin in main raw material blending calculation by a calculation model according to the present invention which is an example.
[Explanation of symbols]
1 ... Blow [C] prediction calculation, 2 ... Steel output temperature prediction calculation, 3 ... Converter auxiliary material input calculation, 4 ... Alloy iron input calculation, 5 ... Converter iron balance calculation, 6 ... Converter heat balance Calculation, 7 ... Main raw material blending calculation, 8 ... Dephosphorization processing calculation.

Claims (2)

The molten iron temperature is 1250 to 1350 ° C., [C]: 3.5 to 4.5 mass%, [Si]: 0.10 mass% or less, and [P]: 0.005 to 0.050 mass%. In addition, the hot metal that has been dephosphorized in advance in the hot metal stage before the charging of the converter is charged into a 70-350t scale upper bottom blowing converter and subjected to decarburization and / or dephosphorization. At the time of controlling the blending calculation of the main raw materials such as hot metal, scrap, and cold iron using a computer,
In the blowout [C] prediction calculation, the blowout [C] is determined, and using this blowout [C], the outgoing steel temperature is calculated in the outgoing steel temperature prediction calculation, and further, the blowout [C] Using the steel output temperature, calculate the auxiliary material input amount in the converter auxiliary material input amount calculation, and use the blowout [C], the steel output temperature, the auxiliary material input amount, and the alloy iron input amount Calculate the iron alloy input by calculation,
Using these calculation results, iron balance calculation and calorie balance calculation in the converter,
A converter characterized in that the main raw material is blended by accurately performing the main raw material blending calculation by transferring data at least once between the iron balance calculation and calorie balance calculation and the main raw material blending calculation. The main raw material blending method. After dephosphorization treatment in the top-bottom blown converter, after dephosphorization slag was removed, the temperature remained in the furnace was 1250 to 1350 ° C., [C]: 3.5 to 4.5 mass%, [ Si]: 0.10 wt% or less, [P]: 0.005 to 0.050 mass% with no thermal margin molten iron again, the time of performing decarburization and / or dephosphorization treatment claim 1 The main raw material mixing method of the converter described in 1.

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