JPS61157607A - Production of molten iron for casting and molten iron for steel making - Google Patents

Abstract

PURPOSE:To produce consistently both molten iron for the castings and molten iron for the steel making in high degree of accuracy of Si in the same blast furnace by setting the objective Si value of each molten iron, blowing the molten iron and performing the silicifying or desilicifying treatment in accordance with the directed parts. CONSTITUTION:In the molten iron blown into a blast furnace 1, the objective value of Si is preset between the various representative Si values for the castings and the seel manufacture. The silicifying quantity or the desilicifying quantity is indicated in accordance with the directed parts of pig iron for the castings or for the steel manufacture from a blast furnace process computer 15 and a silicifying agent or a desilicifying agent is automatically discharged from a hopper 4 or 5. The measured value of the introducing quantity is inputted from a temp. measurement sampling device 7 and the introduction velocity is controlled on the basis of the objective specification. The pig iron for the castings after the pig iron receipt is slagged off in a slag off device via a stirrer 11 and directed to a pig casting machine 10. The pig iron for steel making desilicified is slagged off in a slag off device 12 and sent to a converter works. Thereby the pig iron for the steel making and the pig iron for the castings can be stably produced in the same blast furnace in the minimum cost such as the energy balance of a factory.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to the production of hot metal for foundries and hot metal for steelmaking, and in particular, the present invention relates to the production of hot metal for foundries and hot metal for steelmaking in the same blast furnace in subsequent processes. Information-based flexibility,
Furthermore, the present invention provides a manufacturing method that can be distinguished from conventional methods in that it can be manufactured at low cost.

C) Conventional technology and its problems) Hot metal for casting and hot metal for steelmaking are manufactured based on the standards of each country and the standards of each company, such as JIS and STM. It is known that the production composition (inventory) of pig iron species is affected.

Therefore, the production of hot metal for casting and hot metal for steelmaking is 弼　Produced by blowing in a blast furnace dedicated to the husband.

(a) If the hot metal for steelmaking blown in a blast furnace is lined with force V material, then F
It is also known that there is a method of producing hot metal for casting by adding e-84 alloy (such as Japanese Patent Publication No. 46-30925 J1).

The manufacturing method (7) is the most stable manufacturing method that has been inherited even today, 100 years since the birth of modern steelmaking in Japan, but it requires a dedicated blast furnace, so the equipment costs are huge. Not only that, but labor costs, raw material costs, fuel costs, and other costs also increase. Accordingly, with the production method of Mano ■, production costs cannot be reduced unless the production volume exceeds the break-even point of the design specifications of the blast furnace and its ancillary equipment, so depending on demand trends (production structure), it may be possible to stop the blast furnace. There is a critical issue that must be resolved.

On the other hand, the production method (A) has the advantage of solving the problem of the production method (7), but has the disadvantage that the siliconization cost and the variation in the hot metal [Sil] value depend on the addition yield of the siliconization material. be. That is, the production method (a) uses hot metal for steel production tapped from a blast furnace, but the (8i) value of the hot metal usually fluctuates daily and monthly as shown in the graph of FIG. Therefore, since hot pig metal whose (8i) varies in this way is used as it is, the conditions for adding silicon material are of high quality each time, and since it is added and dissolved from low (Si) to high (Si) (Sil value also tends to fluctuate). This cannot be avoided and the yield decreases. Therefore, the fluctuation of the [St] value of the hot metal itself, and the [SL] after the silicon material temperature lJ
It is not possible to stably produce a large quantity of the intended foundry hot metal due to factors such as the accuracy rate of the value.

Furthermore, in the manufacturing processes (7) and (a), there is no consideration for production with flexibility that can respond to production information in subsequent processes.

Therefore, the above-mentioned technology has the problem of not being able to cope with today's trend of strong needs for small lots and a wide variety of products, and the emergence of a new production system has been eagerly awaited.

In view of the current situation, the inventors of the present invention have made numerous attempts and have found that operations (work), personnel, quality, supply and demand, and other production factors can be handled with 7 flexibilities for small-lot, multi-product production on an industrial scale. We have invented a new method for producing hot metal for foundries and hot metal for steelmaking.In other words, the present invention enables the production of hot metal for castings and hot metal for steelmaking in the same blast furnace at all times at the minimum production cost of an integrated steelworks. The operation is capable of handling hot metal for foundry (8i
) It is possible to improve the accuracy rate, Medium It is possible to adjust production personnel to production, such as by arranging production personnel so that they can work only for the production of hot metal for castings, the amount of iron tapped by adjusting the umbrella [Si], BFG It is designed to solve technical problems such as no fluctuation in the amount generated, stable conditions inside the furnace, reduced damage to the furnace wall, and easy production of a wide variety of products in small lots on a medium-to-industrial scale. .

(Means for Solving the Problems) In other words, the present invention provides that when hot metal for casting and hot metal for steel making are constantly produced in the same blast furnace, the representative (S
i) target (S) based on at least the production mix between the values;
i) blowing hot metal by setting a value, and distributing the hot metal to blast furnace and at least a distribution set based on the production information of the post-process
i) A method for producing hot metal for casting and hot metal for steelmaking, which is characterized by assigning destinations based on values and performing siliconization or desiliconization treatment depending on the destination. State the reason.

[About the same blast furnace]

The premise of the present invention is that hot metal for casting and hot metal for steelmaking are blown in the same blast furnace. Blowing hot metal for foundries and hot metal for steelmaking in a blast furnace exclusively for the husband and husband has limits on production costs and productivity. It is necessary to blow it.

Furthermore, even in terms of investment costs, it is more advantageous than producing by separately installing a dedicated blast furnace.

All of these are essential conditions for minimizing the total value of the energy cost, blast furnace blowing cost, and other production costs of molten pig iron in an integrated steelworks.

[About blowing hot metal by setting a target [S1] value based on at least the production composition ratio between the representative [SI] values of hot metal for casting and hot metal for steelmaking] Representative (sB value and The representative (8i) value of hot metal for steelmaking is desirable on the steelmaking blow line,
The [Sil value, which is representative of hot metal for foundry [8i] and enables blast furnace operation, is set for each pig iron type standard (8i:
It means the weighted average value of l value according to production volume.

In the case of hot metal for back steel, the representative (Si) value of each of the above hot metals is determined by determining the desired quality of hot metal on the steel blowing line from the aspects of heat quantity, slag amount, and blast furnace operation (sB range), In the case of hot metal for foundries, it is determined for each type of pig iron to be blown (8i
) standard and the production amount for each standard, the weighted average (8i
) determined by the value.

The target [Si] value is calculated based on the production composition ratio between the representative [:8i] value of hot metal for casting and the representative [8i] value of hot metal for steelmaking,
Blast furnace operation target (St) set considering production costs, etc.
It is a value.

In the present invention, hot metal for casting can be produced with minimum production cost.

The prerequisite is to produce hot metal for steelmaking, and for this reason, it is not possible to minimize the production cost by simply performing blowing with the above-mentioned hot metal (Si) value within the (8i) value range of hot metal for casting and hot metal for steelmaking. If this is not the case, the purpose cannot be achieved. It is necessary to set a target (8i:) value because it is necessary to have a precondition for minimizing the production cost within the range of the representative (Si) value of each hot metal.

This target (8i) value is set based on at least the production composition ratio of hot metal for casting and hot metal for steelmaking. In this setting, setting based on the following requirements in addition to the production composition ratio is also a subject of the present invention.

That is, the setting of the hot metal target (Si) value is based on the blast furnace blowing cost and the in-house energy cost, as shown in FIG. Converter blowing cost 35. Addition cost: 36° De-siliconization cost: 37.
It is determined based on a total of 38 of these.

Here, the blast furnace blowing cost is calculated based on the fuel unit, air blowing unit, hot blast furnace heat unit, and blast furnace gas generation unit, and the converter blowing cost is the oxygen unit.

It is calculated based on the basic unit of auxiliary materials, the basic unit of furnace material, and the basic unit of converter gas generation, and the in-house energy cost is based on the basic unit of blast furnace gas generation, the basic unit of converter gas generation, the basic unit of coke oven gas generation,
It is calculated based on the unit consumption of gas such as heating furnaces and hot blast stoves, the unit electricity consumption of each factory, the xi generated by surplus gas, and the unit consumption of purchased energy such as heavy oil, coal, and electricity.

Generally speaking, the blast furnace hot metal (Si) value is, for example,
As shown in Publication No. 7725, the height of the cohesive band plate, the SiO2 activity in the slag, the hot metal temperature U, the partial pressure of CO gas, the pig iron output ratio,
Determined by the furnace height conversion index.

The height of the cohesive strip is determined by the in-furnace heat flow ratio based on the fuel ratio setting.

Therefore, the hot metal target (St) value of the present invention is related to the fuel ratio, and is set at the point that minimizes the cost, including the in-plant gas balance.

[The hot metal is distributed to destinations based on the distribution (St) value, which is set based on the production information of the blast furnace and at least the post-process.]

Post-process production information refers to information on production plans, processing timing, equipment, operational troubles, etc. in iron casting factories, steel factories, etc. that require hot metal.

In blast furnace operation, fluctuations in Si3 are inevitable.

(The sB value is distributed near the target (Sill), and under normal operating conditions, the standard deviation is about 0.1 inch.

As shown in FIG. 5, the distribution (St) value 40 is (8
i) The lower limit of the [Si] value for foundry hot metal (Si) considering the variation in the blast furnace hot metal (St:) value blown based on value 39 and the production composition ratio of foundry hot metal and steelmaking hot metal (= steelmaking hot metal This refers to the upper limit of the hot metal direction (8i) value).

The determination of the distribution [81] value varies depending on the operating method, production, and economic environment, and also varies depending on the operating status of the blast furnace.

In other words, the blast furnace operation is stabilized and iron is tapped from the blast furnace (8i)
In a case where the average value and the variation of , do not change from day to day, this distribution (Si) value may be a constant value. However, if the blast furnace operation is unstable and the average value and dispersion of iron tapped from the blast furnace (St) differs from day to day, the distribution (St) will be distributed according to the distribution on that day.
8i) By setting a distribution (si) value that changes the value, hot metal with a high Si:I value can be distributed to hot metal for casting, and hot metal with a low Si value can be distributed to hot metal for steelmaking. The amount can be reduced and the cost can be lowered.

[Determining the destination based on the distribution (8i) value] Determining the destination based on the distribution (811 value) means whether the hot metal tapped from the blast furnace is to be used for casting or for steelmaking. means to decide.

In addition, statistical methods can be used to predict the relationship between blast furnace operation data and (Si) values over several tens to hundreds of hours of overwork, and the coefficients of the relational equation are determined based on statistical regression methods.
i) It can also be done by a method of predicting the value.

Furthermore, the hot metal was actually measured, that is, sampled in the blast furnace hot metal gutter,
(Si), or by continuously measuring the components of hot metal that is tapped.In this case, theoretical predictions, predictions using statistical methods, and actual measurements may be performed alone, or The destination can also be determined based on the distribution υ Si' value by a combination of theoretical prediction and actual measurement, a statistical method and actual measurement, or a combination of theoretical prediction, statistical prediction, and actual measurement.

[Depending on the destination, siliconization or desiliconization treatment is required.]

Refining means increasing the [S1] value with respect to hot metal, and examples of refining materials include Fe-8i alloy and 81-Mn.
Use alloys, etc. Moreover, desiliconization means to reduce the (S;) value of hot metal, and examples of the desiliconizing material include scale, sintered ore, pig iron ore, and dust.

In this case, it depends on the level of production information in the post-process.

In order to make hot metal for steelmaking, add a silicone-reducing material to hot metal for casting, or add silicone-retaining material to hot metal for casting to make hot metal for high-silicon casting, or add silicone-removal to hot metal for steelmaking. Silicification treatment and desiliconization treatment are carried out by adding materials to make hot metal for low-silicon steelmaking, and further adding silica materials to hot metal for steelmaking to make hot metal for casting. It is sufficient to utilize various advanced processing technologies.

(Function) The present invention will be described below based on an implementation diagram shown in the drawings.

FIG. 1 is an explanatory diagram showing the main processes of a steel mill that implements the present invention.

In the figure, 1 is a blast furnace, 2 is a large gutter, 3 is a branch gutter, 4 is a siliconizing agent hopper, 5 is a desiliconizing agent hopper, 6 is a charging chute, 7 is a temperature measurement sampling device, and 8 is a hot metal ladle.

9 is a weighing machine, 10 is an iron casting machine, and 11 is a stirring device.

12 is a slag removal device, 13 is a converter, 14 is a production control computer, 15 is a blast furnace procorn, and 16 is an electrical connection circuit.

FIG. 2 is an explanatory diagram showing the main parts of the system shown in FIG. 1 in enlarged blocks, and the relationship between production control and operation of the manufacturing process shown in FIG. 1 can be understood from this diagram.

That is, to explain an example of the Sikinai Mei method with reference to FIGS. 1 and 2, the blast furnace 1 is the same blast furnace, and the hot metal (Si) value is representative of hot metal for casting and hot metal for whitening. Blowing between values.

The operating technology of the blast furnace 1 at this time is well known.

The production control plan is transmitted from the production control computer 14 to the terminals of each production process. Based on this information, the [Si] target value for the hot metal (8i) to be blown in the blast furnace 1 is set between the representative (Si) values for foundry hot metal and steelmaking hot metal.This [S1] target value - The energy cost of the steelworks, for example, the heat sources used and generated in the steelworks (solid, liquid, gaseous fuel, electricity) and the energy cost t
Set so that the total value of the blast furnace and converter blowing costs excluding t-, and the siliconization and desiliconization costs is minimized. In this setting, the blast furnace 1 is operated mainly by changing the coke ratio and the blown fuel ratio, as well as the operating conditions, so as to maintain the energy balance of the steel mill and to minimize costs at the same time.

Thus, the hot metal blown in the blast furnace 1 is tapped through the large gutter 2, and is introduced into the hot metal ladle 8 through the branch gutter 3. If you want to direct the hot metal to casting pig or steelmaking piglet based on the distribution (Si) value during the taping interview, you can use the theoretical method to predict (8i) inside the furnace using blast furnace procon 15, or It may be determined using statistical methods, mass sampling and rapid analysis, or direct analysis and this operation. Of course, before tapping, the amount of hot metal to which the next tap is to be directed is determined in advance by the production control computer 14 based on the order conditions and production conditions for that day, and is input into the AP processor 15.

5 Here, we will explain in detail the contents related to computer production based on Figure 2. Product orders are generally entered into the production management computer 14 in lot units. Furthermore, this is incorporated into the monthly plan using the monthly planning system 18. In this, the relationship between the product production schedule and the amount of casting pig iron and cracked steel pig iron is roughly determined, but in addition, the daily planning system 19
The most recent production order information is used to break it down and presented to the production manager 24.The production manager 24 checks it and presents the final order to the process adjustment center 22, based on the production information at the time. Further, some adjustments are made and the information is transmitted to the blast furnace process controller 15.

The processing contents of the blast furnace process controller 15 are shown in FIG. 2. After receiving the production order within two days, receiving the required amount of pig iron received by tap 26. Prediction 27 (theoretical or statistical) or actual measurement data of Si temperature by pot.

Production of pig iron for preparatory casting and steelmaking is determined 28. Casting iron standard determination 29. Addition and removal siliceous calculation 30. Addition silicon work instructions 31,
(Sr) Actual value reception 32. Addition/removal silica correction calculation/instruction 3
Do step 3.

In this way, the blast furnace program controller 15 issues instructions for the destination of the casting pig or steelmaking pig and the amount of siliconization and desiliconization depending on each destination, and based on these instructions, the process is automatically carried out to the silica agent hopper 4 or the desiliconization amount. Added and removed silica is automatically cut out from the agent hopper 5. At this time, the charging speed of the addition/removal silicon agent is controlled according to the output of the scale stitching machine 9 so that the silicon removal efficiency is maximized. Further, as soon as the actual measurement value is inputted from the temperature measurement sampling device 7, the successive feeding speed is controlled based on the target standard.

In the case of casting pig iron, the pot which has finished receiving pig iron in this way is stirred by the stirring device 11.
After passing through the bluff and being mixed uniformly, the sludge is removed from the bluff by a slag removal device and sent to the iron casting machine 10.

On the other hand, in the case of desiliconized steelmaking pig iron, the desiliconized pig iron is removed by a slag removal device 12 and sent to a converter factory.

In this way, the same blast furnace can constantly and stably produce steelmaking pig iron and foundry pig iron in response to the demands of each factory, without making any major changes to the operating specifications of the blast furnace.
Produce at minimum cost by maintaining energy balance within the plant. In addition, we will achieve the demand plan (production plan) for small-lot, high-mix production.

(Execution sequence) The method of the present invention is as described above, and these will be further specifically explained using an implementation sequence.

The conditions for this implementation row are as shown in Table 1.

Table 1 (Implementation Column 1) In this execution column 1, using the variation in the blast furnace blowing line near the [8i:] target value, and taking into account the demands of the post-process and this variation, high-Si hot metal is converted into foundry hot metal. In addition, low 8i hot metal was distributed to steelmaking pig iron. 1150m' blast furnace with monthly production of 6
0,000 tons of iron was tapped, of which 18,000 tons
Production was planned to produce 42,000 tons of iron for casting and 42,000 tons of iron for steelmaking. The pig iron type composition of foundry pig iron is as shown in Table 2.

Table 2 From this table, the representative (SL) value of foundry pig iron was determined to be 1.57%. On the other hand, the representative (Si) value of steelmaking pig iron was determined to be 0.60% from the operational standpoint of the Tsubame factory.

Next, in order to obtain the hot metal [Si] target value, the energy cost of the steelworks is considered, the blast furnace blowing cost is calculated, the converter blowing cost and the silica cost are plotted, and the additional pressure is calculated. When the total value was plotted, the result was as shown in FIG. 7, and the hot metal target (Si) value was set to 100 进. Table 3 shows the operating results of the blast furnace. From Table 3, taking into account that the standard (2) difference in blast furnace (Si) value is 0.13 cm, the production ratio of casting pig iron is 30 cm, and the production ratio of steelmaking pig iron is 70%.
Si] value was set at 10.7%. This distribution (S
i:] Depending on the value, tap iron (:8i) is converted into 8 units of hot metal ladle (receiving pig iron amount 50t/ladle).If (Si) exceeds 1.07, it is used as casting pig iron, and if it is less than 1.07 inch, it is used as steelmaking pig iron. I took pictures separately. For the first pot after tapping, the shooting is carried out based on the theoretical prediction (8i) estimated value using the furnace loading conditions, air blowing conditions, furnace top gas composition, hot metal temperature, components, furnace reaction, etc. From the second pot onwards, the actually measured (8i) value by the sampling device 7 was used.

Table 3 Table 4 shows the column for this photographic amount and the adjustment for addition/removal.

Table 4 Table 5 shows the scale used and the composition of Fe-8i.

In the case of this implementation series, the target 8i value and the 8i value of the blast furnace blowing result are
1 value, and the standard deviation of Si is 0.13%, which is a constant value every day, so there is no need to consider deviation from the target value due to fluctuations in blast furnace operation when setting the distributed St value. Production was possible using a method set from a normal distribution table based on the production composition ratio of hot metal and steelmaking guns.

In the process after the converter, there are cases where steelmaking pig iron is required continuously at a rate higher than the blast furnace production rate, and as before, the slag removal system [12
A mixed pig iron furnace (capacity 200 tons) was installed between the converter 13 and the converter 13 for operation.

As a result, the blast furnace base can stably produce foundry pig and steelmaking pig.
It can be supplied at all times, the blast furnaces can be consolidated as shown in Tables 6 and 7, and the production volume and quality are the same as in the case of two blast furnaces, reducing fixed costs and improving labor productivity. . In addition, as shown in Table 8, when comparing blast furnace blowing, refining from steelmaking pig iron, and the present invention in terms of the accuracy rate of cast iron blowing,
It can be seen that the present invention improves by about 15%. Furthermore, we were able to reduce the inventory of casting pig iron. Furthermore, Table 7 shows a comparison of the components produced, and there is no inferiority to the conventional method, and there were production operations and effects that were not seen in the conventional method.

Table 7 (Implementation Column-2) In this implementation stage 1, the types of pig iron produced were concentrated on casting pig or steelmaking pig depending on the time of day. The distribution changed depending on the time of day.

Originally, foundry pig iron blast furnaces were an unbalanced process in ironworks, where the amount of blast furnace gas generated was large, but the only consuming process was the iron casting machine. Therefore, this generated gas was mainly used for power generation. On the other hand, when the company had a cast iron blast furnace, it was not possible to adjust production by drastically increasing or decreasing the amount of air blown on an hourly basis to ensure stable blast furnace operation. However, according to the method of the present invention, the amount of electric power purchased could be freely adjusted to one pillar by simply adjusting the destination of the blast furnace within a day while the production volume of the blast furnace was constant.

Applicants have proposed that in a steelworks with a power balance as shown in Table 9, peak hours in the summer (3 hours), daytime hours (11 hours),
In Hr), the setting of the distribution h value is stopped, all the hot metal tapped from the blast furnace is used as hot metal for foundries, and production is concentrated on hot metal for foundries, especially.

The converter and blooming processes were suspended during peak hours. As a result, when the production volume was 60,000t/M, the average amount of electricity purchased was 1
7000 Kwh/) Tr, 5000 Kwh/
This made it possible to reduce the amount of electricity purchased per hour, contributing greatly to cost reductions and to electricity supply and demand.At the same time, depending on this production method, production personnel within the plant could be reduced to 8 hours across peak hours.
An irregular staffing arrangement was adopted in which hours were set aside for the operation of the pig iron casting machine, and processes after the converter blooming were carried out during other hours.

Table 9 As a result, we were able to reduce the amount of purchased electricity during peak hours without increasing the number of on-site personnel, and we were able to stably produce foundry pig iron and pear steel pig iron.

(Execution 03) This implementation series corresponded to the fact that the blast furnace operation was unstable and the target S1 fluctuated daily.

That is, in the rows in FIGS. 4 and 5, the target Si is determined in the same way as in the first row, and in FIG.
This is a case in which the frequency of St is concentrated around the target value in time series, and the distribution does not change even if the frequency graph of St is drawn for each day.However, Fig. 5 shows that the blast furnace blown Si is in poor operation with respect to the target of 5i39. Therefore, the rows are shifted toward the high Si side, and the rows shown in FIG. 5 are targeted for the third embodiment.

The distribution [S1] value needs to be automatically determined according to fluctuations in the blast furnace (Si) value, but this has been possible by statistically predicting it from past data. That is, the past fluctuation trends were aggregated for each pot for 10 days, and the [8I] distribution was apportioned according to the production composition ratio of the day to determine the distribution 81 value.

As shown in Table 10, the average Si value for one blast furnace was 1.10% with respect to the target Si value of 1.00%, and the standard round difference was 0.13%. The production composition ratio was 30% hot metal for casting and 70% hot metal for steelmaking.

Therefore, as in implementation column 1, the distributed Si value is 1.07
If the percentage is left unchanged, according to the normal distribution table, hot metal for steelmaking with a content of 1.07% or less will be 41L%, and hot metal for castings with a content of 1.07% or more will be 69%, which does not match the production composition ratio. Therefore, it is necessary to correct the deviation of the blast furnace average Si value from the target Si value, and in the case of this implementation series, the distribution Si
The value was set to 1.18%.

Table 10 Table 11 shows the results of applying this method to a period when [Si,:l] was high due to poor furnace conditions as shown in Figure 7.

As a result, it was found that 70% of the steelmaking pig iron and 30% of the casting pig were distributed as planned.

In this way, this method can be applied even in cases where the furnace conditions are unstable, the steelmaking pig iron can be supplied stably, and the accuracy rate has the same effect as shown in Table 2 already mentioned. can be,
It improved labor productivity and reduced inventory, producing production operations and effects not seen with conventional methods.

(Effects of the Invention) As described above, the present invention has the following effects and achieves the intended purpose.

- The same blast furnace can constantly produce hot metal for foundries and hot metal for steelmaking at the minimum production cost of an integrated steelworks.
S1] It is possible to improve the accuracy rate, medium It is possible to make adjustments to accommodate the production of production personnel, such as lining up production personnel so that they can only work in the production of foundry pig iron.

1 (81) Due to adjustment, there is no change in the amount of tapped iron or EIFG generation, the situation inside the furnace is stable, and damage to the furnace wall can be reduced.It is possible to reduce power consumption by adjusting production during peak hours in the summer. , the power can be adjusted, the fixed cost of the skewer blast furnace can be reduced, and the amount of capital investment can be reduced.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the process of carrying out the present invention, Fig. 2 is a block diagram explaining the main parts of the system shown in Fig. 1, and Fig. 3 is a diagram showing changes in blast furnace tapped iron [Si:] [S1]. Figure 4 is a diagram showing an example of a change in blast furnace tapped iron [St:] with a large variation in (Si); Figure 5 is a diagram showing an example of a change in blast furnace tapped iron [St:] with a large variation in (Si); ) value, FIG. 6 is an explanatory diagram of a method for setting the (Si) target value that minimizes cost, and FIG. 7 is a diagram showing a sequence of [Si] fluctuations when the furnace condition deteriorates. 1... blast furnace, 2... gutter, 3... Giken, 4...
Silica additive hopper, 5... Silica removal hopper, 6... Input chute, 7... Side temperature sampling device! 3...
・Hot metal pot, 9... Weighing machine, 10... Casting machine, 11.
... Stirring device, 12... Slag removal device, 13... Converter,
14... Production control computer, 15... Blast furnace processor, 16... Electrical connection circuit, 18... Monthly planning system, 19... Daily planning system, 20...
Production command system, 21... Computer guide (OELT)
), 22... Process adjustment center, 24... Production manager, 25... Converter processing controller, 26... Reception of required hot metal molten iron by tap, 27... Preparation Si-temperature prediction, 28.
... Pig production υ for preparing and casting iron is determined, 29 ... Standards for casting pig iron are determined, 30 ... Silica weight calculation, 31 ...
・Additional silicon work instructions, 32...(81) Actual value reception, 3
3... Calculation and instruction for correction of silica content, 34... Blast furnace blowing cost and in-house energy cost, 35... Converter blowing: ffs)% 36... Addition silicon cost, 37...・Siliconization cost, 38...Total cost of 34 to 37, 39...
- Target [Si] value, 40...distribution [st] value. Agent: Patent Attorney Masamitsu Aki Sawa and 2 other persons. 76 Figure 1 Day Off Figure Voluntary Procedure Amendment Letter February 6, 1985

Claims (1)

[Claims] (1) When constantly producing hot metal for casting and hot metal for steelmaking in the same blast furnace, set a target [Si] value between the representative [Si] values of each hot metal husband and husband, based on at least the production composition ratio. blowing hot metal, sorting the hot metal to destinations based on the distribution [Si] value set based on the production information of the blast furnace and at least the post-process, and subjecting it to siliconization or desiliconization depending on the destination. A method for producing hot metal for casting and hot metal for steelmaking, characterized by: