JPS5938289B2 - Method for producing sintered ore - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for obtaining sintered ore with stable drop strength, reduction powdering rate, etc., which are important for quality control in the production of sintered ore.

Koki, which stably secures sintered ore of appropriate quality, is an extremely important factor for stable operation of a blast furnace over a long period of time.

In order to stably obtain sintered ore of appropriate quality, it is necessary to accurately grasp predicted information such as drop strength and reduction powdering rate during the sintered ore manufacturing process, and use this information to quickly determine the supply amount of blended raw materials. It is necessary to provide feedback for adjusting operating conditions such as charging density and moisture content.

However, in conventional quality control of sintered ore, in the cooling process that is the next step after the sintering process, samples are taken from the cooled sintered ore and the drop strength and reduction powdering rate are measured. Therefore, there is a time difference of 2 to 3 hours between the time when the operating conditions are set and the time when information on sinter obtained under those operating conditions is obtained. It was normal.

Therefore, it was not possible to take prompt measures to obtain sintered ore of appropriate quality, and it was therefore extremely difficult to obtain sintered ore of stable quality.

The present invention was created in view of the above-mentioned drawbacks of the conventional art and for the purpose of eliminating them.

The gist of the present invention is to predict the falling strength and reduction powdering rate during the production of sintered ore and control the operating conditions for the production of sintered ore. While the pallet conveyor in the equipment is running, the layer thickness of the compounded material is measured between the feeding position of the compounded material and the ignition furnace, and the thickness of the sintered ore layer is measured at the position just before the ore discharge port to determine the sintering of the compounded material. The sintering rate is compared with a preset target sintering rate to find the deviation value, and based on the deviation value, the supply amount of the blended raw material, the moisture content of the blended raw material, and the drive speed of the pallet conveyor are determined. By controlling the control elements such as the above, it is possible to obtain sintered ore of stable quality.

As a result of various studies on the relationship between the sinter compaction rate of sintered ore and the quality of the sintered ore, the present inventors found that the sinter compaction rate due to sintering of the sintered raw material depends on the drop strength, reduction powdering rate, and production rate. I discovered that there is a close relationship between

That is, FIG. 1 shows the relationship between the sintering rate, falling strength, reduction powdering rate, and production rate for the same raw materials as those used in Examples described later.

From the same figure, it can be seen that the L drop strength increases by increasing the sintering rate of the blended raw materials, but the production rate decreases.

This is because the molten material within the sintered layer aggregates due to an increase in the sintering rate, which impedes air permeability.

However, it can be seen that when the sintered compaction rate is decreased, the air permeability within the sintered layer improves and the production rate improves, but the drop strength of the sintered ore decreases.

Also, looking at the reduction powdering rate, it can be seen that when the baking compaction rate is increased, the reduction powdering rate decreases like the production rate, and conversely, when the baking compaction rate is decreased, the reduction powdering rate increases.

The relationship between the sintering rate of the sintering raw material, the falling strength of the sintered ore, the production rate, and the reduction powdering rate is as described above, but the details (
Needless to say, there are some variations depending on the conditions of the raw materials to be mixed.

However, the optimum compaction rate of the blended raw materials is approximately 15~
If the sintering rate is less than 15%, the drop strength will decrease and it will no longer be possible to use it in a blast furnace.
%, there is a risk that the production rate will decrease and cause economic loss.

Hereinafter, an apparatus for carrying out the method of the present invention will be explained.

FIG. 2 is a schematic explanatory diagram showing the entire main part of the sintered ore production facility.

In the figure, 1 is a pallet conveyor that sequentially conveys a large number of pallets in the direction of the arrow.

A bedding raw material hopper 2 is installed at the upper blade portion of the pallet conveyor 1 near the right end.

The bedding material stored in the bedding material hopper 2 is supplied and laid on the floor surfaces of pallets that are sequentially conveyed by the pallet conveyor 1.

A compounding material hopper 3 is installed adjacent to the bedding material hopper 2, and a roll feeder 4 is provided at the lower end of the compounding material hopper 3.

The blended raw material for sintered ore stored in the blended raw material hopper 3 is fed through the chute 5 by the rotation of the roll feeder 4 onto the bedding raw material laid on the pallet.
As the pallet conveyor 1 moves, the pallets are sequentially conveyed.

When the amount of blended raw materials supplied is greater than the amount of blended raw materials conveyed, the excess blended raw materials are deposited at the front lower part of the chute 5.

When the charging bulk amount of the deposited mixed raw materials increases, the density of the mixed raw materials on the pallet increases, and conversely, when the charging bulk amount decreases, the density of the mixed raw materials decreases.

Therefore, the charging bulk at the front lower part of chute 5 is calculated as the total charging bulk 9.
The density of the blended raw materials is adjusted based on the measured value.

An ignition furnace 6 and a heat retention furnace 7 are located above the center of the pallet conveyor 1 at a slight distance from the position of the raw material hopper 3.
is installed.

When a pallet loaded with a certain amount of blended raw materials is transported to the ignition furnace 6 and heat retention furnace 7, the blended raw materials are ignited while passing there, and transport and sintering proceed as time passes. do.

In the method of the present invention, an important means is to measure the layer thickness of the blended raw materials and the layer thickness of the sintered ore. The layer thickness of the produced sintered ore is measured by the raw material layer thickness measuring device 8 installed at the ore outlet 11 between the heat retention furnace 7 and the sintered ore outlet 11
Measurement is performed using a sintered ore layer measuring device 10 installed at the immediately preceding position.

The sintered ore 12 obtained by completing the sintering is transported while being loaded on a pallet, falls from the ore discharge port 11 at the left end of the pallet conveyor 1, and is crushed and taken out.

FIG. 3 is a block diagram for explaining the control system in the method of the present invention.

The layer thickness of the blended raw materials is measured by the raw material layer thickness measuring device 8, and the layer thickness of the sintered ore is measured by the sintered ore layer thickness measuring device 1.
It is 0.

The measured layer thickness values of the blended raw materials and sintered ore are sent to the compaction rate calculating device 13, and the compaction rate is calculated.

As an example, the shrinkage rate is calculated using the following formula.

However, A: Measured raw material layer thickness B: Sintered ore layer thickness measurement value In the same figure, 14 is a shrinkage weight setting device.

In this sintering mass setting device 14, the most suitable target sintering mass ratio is selected from a range of 15 to 30% based on the conditions of the raw materials currently being sintered.

The specific target compaction rate that is actually set is determined empirically according to the names of the raw materials and their blending ratios.

However, even if the layer thickness value of the blended raw materials is the same, the density of the blended raw materials varies depending on the bulk of the charging material due to the raw materials deposited at the front lower part of the chute 5, and this causes the sintering rate during sintering to decrease. also changes.

Therefore, in order to control the sintering operation, it is necessary to transmit a signal of the actual value measured by the charging bulk height meter 9 to the main processing unit 19.

Thus, the main computing device 19 includes the shrinkage rate computing device 13.
The measured compaction rate from the machine, the target compaction rate from the compaction weight setting device 14, and the blended raw material condition values from the raw material condition setting device 15 are input, respectively.

The main processing unit 19 inputs the conditions of the raw material mixture from the raw material condition setting device 15, thereby setting a charging density value suitable for the conditions of the raw material mixture currently being sintered, and determining the charging density value that is suitable for the conditions of the raw material mixture that is currently being sintered. II of moisture value and pallet conveyor speed
The J value is determined, and appropriate values are calculated for each.

In addition, the main processing unit 19 compares the preset and input target shrinkage percentage with the measured shrinkage percentage that is continuously input from the one-heat shrinkage calculation device 13, and compares the measured shrinkage percentage with respect to the target shrinkage percentage. A deviation value is calculated, and based on this deviation value, the charging density value of the blended raw materials, the moisture content value of the blended raw materials, and the drive speed of the pallet conveyor are successively corrected and adjusted.

An example of the modification will be explained as follows.

That is, in the main processing unit 19, as a result of comparing the set target shrinkage percentage and the measured shrinkage percentage sent from the shrinkage percentage calculation device 13, it is determined that the value of the measured shrinkage percentage is large. If this happens, a signal is sent to the roll feeder controller 16 to shift the sintered ore compaction rate to a smaller value, and the rotational speed of the roll feeder 4 is increased to increase the charging density. Ru.

If the charging density is outside the limit within the main processing unit 19 even after adjusting the speed of the roll feeder 4, the water flow controller 17
A signal is sent in the direction of decreasing the shrinkage rate, and the moisture content of the blended raw materials is adjusted to decrease.

If both the charging density value and the water content value of the blended raw materials are still outside the set limit values even after adjusting in this way, a signal is sent from the main processing unit 19 to the pallet conveyor speed controller 18, and the pallet conveyor speed is adjusted. Adjust the drive speed to be faster.

If it is determined that the measured shrinkage ratio is smaller than the target shrinkage ratio, correction and adjustment are performed in the same manner as described above, but in this case, the direction of the correction is opposite to that described above.

As described above, by outputting correction signals from the main processing unit 19 to the roll feeder controller 16, water flow controller 17, and pallet conveyor speed controller 18, the value of the measured shrinkage rate can always be adjusted to match the conditions of the raw materials. It is designed to match the target shrinkage rate.

In the method of the present invention, the detection section of the raw material layer thickness measuring device 8 and the sintered layer thickness measuring device 10 may be a contact method using a roller or the like, or a non-contact method using ultrasonic waves, gamma rays, etc. It may be of a type.

Also, a pallet conveyor 1 is connected between the ignition furnace 6 and the ore discharge port 11.
A plurality of layer thickness measuring devices 8 and 10 are arranged in the conveying direction of
The generation status of sintered ore may be measured while being managed along its progress.

Furthermore, a plurality of layer thickness measuring devices 810 may be arranged in parallel in a direction orthogonal to the conveyance direction of the pallet conveyor 1, and the control may be performed based on the average measured value thereof.

Furthermore, the layer thickness measurement may be not only continuous measurement but also intermittent measurement.

There is no need to limit the control elements of operating conditions to the three elements of charging density, moisture content, and pallet conveyor drive speed, and the control procedure also depends on the specific sinter production method to be applied. The control may be changed to the one most suitable for the type and process.

Next, an embodiment of the method of the present invention will be described.

According to the conditions of the blended raw materials shown in Table 1, the optimum compaction rate, that is, the target compaction rate, was set at 22%, and the measured compaction rate was controlled so as to approach the target compaction rate.

Regarding the supply of mixed raw materials for this purpose, the rotation speed of the roll feeder 4 is controlled so that the charging density value is in the range of 191 to 1.95 ton/m2 regarding the accumulation state on the pallet at the front lower part of the chute 5. The water content value of the blended raw materials is determined by the water volume controller 17 installed in the mixer.
The moisture content of the blended raw materials was controlled to be in the range of 5.0 to 5.5%.

The results are shown in Table 2. As described above, the method of the present invention improves the quality of sintered ore, aims to define the quality,
Moreover, productivity can be improved, so it is extremely useful in the production of sintered ore.

[Brief explanation of the drawing]

Figure 1 is a relational diagram showing the influence of sintered ore drop strength, reduction powdering rate, and sinter compaction rate on production rate; Figure 2 is an overall schematic diagram showing the main parts of sintered ore sintering; FIG. 3 is a block diagram showing the control method. 1...Pallet conveyor, 2...Bedding raw material hopper, 3...Blending raw material hopper, 4.
... Roll feeder, 5 ... Chute, 6 ... Ignition furnace, 7 ... Heat retention furnace, 8.
... Raw material layer thickness measuring device, 9... Charging bulk meter, 10... Sintered ore layer thickness measuring device, 11...
... Outlet, 12 ... Sintered ore, 13 ...
- Baking compaction rate calculation device, 14... Baking compaction weight setting device, 15... Raw material condition setting device, 16...
...Roll feeder controller, 17...Water flow controller, 1B...Pallet conveyor speed controller,
1B...Main processing unit.

Claims (1)

[Claims] 1. While the pallet conveyor in the sintered ore manufacturing equipment is being driven, the layer thickness of the mixed raw material is measured between the supply position of the mixed raw material and the ignition furnace, and the sintered ore layer thickness is also measured at the position immediately before the ore discharge port, and the sintered ore layer thickness is measured and blended. Calculate the sintering rate of the raw material, compare the sintering rate with a preset target sintering rate, and find the deviation value,
A method for producing sintered ore, characterized in that control elements such as the supply amount of the blended raw materials, the moisture content of the blended raw materials, and the drive speed of the pallet conveyor are controlled based on the deviation value.