JPH046777B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention aims to improve the sintering yield and strength by optimizing the particle size segregation and carbon segregation of the charged raw material in a slit bar charging device of a DL sintering machine. Concerning the method of charging raw materials intended to be improved.

[Conventional technology]

Conventionally, in the steel industry, when producing sintered ore to be charged into a blast furnace, iron ore powder of approximately 10 mm or less is mixed with coke of an appropriate particle size and, if necessary, limestone powder, and then made into a sintered pallet. A sintering machine that ignites the coke on the surface after charging, burns the coke while sucking air downward, and uses the combustion heat to sinter the fine ore (hereinafter abbreviated as DL sintering machine).
is used.

In such a DL sintering machine, sintering progresses through the combustion of coke, so the supply of air to the sintered layer, that is, the quality of the ventilation of the sintered layer, is a major factor that affects productivity. Become.

In this case, if the raw material or coke is distributed with a uniform particle size in the height direction of the sintered layer, due to the characteristics of heat movement within the sintered layer, the temperature will become higher toward the lower layer and the ventilation resistance will increase. Therefore, in a DL sintering machine, the raw materials are charged after performing particle size segregation of the raw materials such that coarse grains are in the lower layer and fine grains in the upper layer of the sintering pallet entering the machine, and carbon segregation is performed to increase the coke content in the upper layer. Then, a sintered layer is formed. In this way, the ventilation resistance within the sintered layer is reduced, the coke combustion efficiency is improved, and the temperature distribution is improved, thereby improving the sintering yield and obtaining high-quality sintered ore.

FIG. 1 is a schematic side view showing an example of a raw material charging device of a DL sintering machine for carrying out the above-mentioned segregation charging. This raw material charging device 1 has an approach plate 3, a slit bar 4, and a lower plate 5 integrally provided above a sintering pallet 2 while maintaining a constant chute angle α with respect to the pallet traveling direction. is composed of a plurality of rods 6 arranged at a predetermined pitch in the width direction of the pallet,
In addition, the run-up board 3 is made up of two overlapping boards 3a and 3b.
The upper plate 3a is slidable so as to cover the upper surface of the slit bar 4. Further, the entire raw material charging device 1 is movable parallel to the pallet advancing direction, and the angle α is also variable. Note that 7 is a deflector chute attached to the lower part of the slit bar 4, and 8 is a cut-off plate for leveling the upper surface of the sintering raw material charged into the sintering pallet 2.

First, the sintered raw material 10 stored in the hopper 9 is cut out from the drum feeder 11, falls onto the run-up plate 3, and further falls onto the slit bar 4 while rolling on the run-up plate 3. In the slit bar 4, the fine particles 10a in the sintering raw material 10 that have passed through the slit bar 4 first fall onto the sintering pallet 2, and the coarse particles 1 that have not passed through the slit bar 4 fall into the sintering pallet 2.
0b falls from the top of the slit bar 4 through the lower plate 5 and onto the sintering pallet 2 from the tip. Therefore, on the entering sintered pallet 2, charging is performed with grain size segregation such that the coarse grains 10b are in the lower layer and the fine grains 10a are in the upper layer.

In the operation of this DL sintering machine, if the production volume and the particle size distribution of the charged sintering raw materials are constant, a sintered layer with almost constant particle size segregation will be formed, but due to changes in the operating rate, the production If there is a change in the amount or raw material composition, the sintering machine is stopped and the sintered layer is sampled to measure the particle size segregation, the ratio of raw materials passing through the slit bar 4, etc., and the raw material is charged to match the operating conditions. By changing the overall position of the device 1, the chute angle α, the rod spacing of the slit bar 4, and the length of the run-up plate 3, the fine grains 10a that pass through the slit bar 5 and the coarse grains 10b that do not pass through the slit bar 4 are adjusted to a predetermined ratio. The particle size distribution was adjusted to maintain the optimum particle size distribution.

[Problem that the invention seeks to solve]

By the way, when charging raw materials, the particle size distribution of the raw materials is constantly changing even during normal operation, and the raw materials may adhere to the rods 6 of the slit bar 4, narrowing the rod gaps, etc. Variations occur in the classification effect.
For this reason, as shown in Figure 2, the optimum particle size distribution of the sintering raw material charged into the sintering pallet 2 is disturbed, causing non-uniformity in the thermal history of the sintered layer, resulting in a decrease in sintering yield and strength. It was the cause of this.

The present invention has been made in view of the above-mentioned problems, and provides a raw material charging method that accurately grasps the segregation state of charged raw materials and improves the sintering yield and strength.

[Means for solving problems]

The technical means of the present invention for solving the above problems is to supply the sintering raw material to a slit bar type raw material charging device that is provided with a constant chute angle with respect to the traveling direction of the sintering pallet, The height of the coarse grain raw material charged into the sintering pallet from the tip without passing through the slit bar, and the total height of the charged raw material after the fine grain raw material that has passed through the slit bar is dropped and charged onto the coarse grain raw material. Measure each with a level meter, calculate the ratio of fine raw materials that passed through the slit bar from the measured values, and evaluate the particle size segregation and carbon segregation of the sintered raw material layer charged to the sintering pallet based on the ratio. A method of charging raw materials for a sintering machine is characterized in that the control elements of the raw material charging device are also adjusted and controlled.

[Effect]

The sintering raw materials charged into the sintering pallet are charged with a certain ratio of coarse grain raw materials in the lower layer and fine grain raw materials in the upper layer, so that optimal particle size segregation and carbon segregation are formed, and ventilation is achieved. This reduces resistance, improves coke combustion efficiency, and improves temperature distribution.

Among the sintering raw materials supplied to the slit bar type raw material charging device, first the height of the coarse raw materials charged into the lower layer of the sintering pallet without passing through the slit bar is measured using, for example, an ultrasonic level meter. The total height of both fine grain raw materials passed through the slit bar and dropped onto the coarse grain raw material is measured with another ultrasonic level meter, and the ratio of fine grain raw material that passed through the slit bar is calculated from these measured values. do. The measurement frequency may be continuous or intermittent, and the ratio may be the proportion of the coarse raw material that does not pass through the slit bar. In any case, any ratio to the total height of the charged raw material may be determined.

The ratio obtained in this way is compared with a predetermined standard value that indicates the optimum grain size segregation, and the grain size segregation and carbon segregation of the raw material sintered layer are evaluated. If there is a difference between the ratio and the standard value, The control elements of the material charging device, such as the position of the entire device, the chute angle, the spacing between the rods of the slit bar, and the length of the run-up plate, are adjusted and controlled, and the amount of material that passes through or does not pass through the slit bar is constantly controlled. Creates optimal particle size segregation and carbon segregation to reduce ventilation resistance of the sintered layer, improve combustion efficiency, and improve temperature distribution.

〔Example〕

An embodiment of the raw material charging method of the present invention will be described in detail with reference to FIG. 1.

The sintering raw material 10 cut out from the hopper 9 via the drum feeder 11 and supplied to the slit bar type raw material charging device descends onto the slit bar 4 while rolling on the run-up plate 3. Here slit bar 4
The coarse raw material 10b that falls from the tip via the lower plate 5 without passing through is deposited at a constant height on the lower layer of the incoming sintering pallet 2.
Further, the fine grain raw material 10a that has passed through the slit bar 4 is deposited on the deposited coarse grain raw material 10b layer to form a sintered raw material layer that maintains a constant height.

A first ultrasonic level meter 12 is installed at the bottom of the lower plate 5, and a second ultrasonic level meter 13 is installed near the front of the cut-off plate 8. The height of the coarse grain raw material 10b charged and deposited in the lower layer is measured, and the height of the fine grain raw material 10b is measured in the second level meter 13.
The height of the sintered raw material layer including a, that is, the total charging height of the raw material is measured. Based on these two measured values, the fine grain raw material 1 that passed through the slit bar 4
Calculate the ratio of 0a.

This ratio is an index that represents the particle size distribution of the raw material in the height direction of the sintering raw material layer. Therefore, if this ratio always indicates a predetermined value, the sintering raw material layer will have the optimum particle size segregation. in a state. Therefore, by comparing this ratio with a predetermined reference value indicating the optimum particle size segregation, it is possible to evaluate the particle size segregation and carbon segregation at the time of measurement.

It is natural that changes in the production volume or raw material composition may occur due to changes in the operating rate of the sintering machine, but changes may occur in the particle size distribution of the raw material during the operation of a series of rods, or changes in the rod of the slit bar 4 may occur. If the raw material is attached to the rod 6 and the rod gap is narrowed, the classification effect of the raw material varies and the ratio of the fine raw material 10a changes,
This fluctuation is immediately detected by the first and second ultrasonic level meters 12 and 13. In this case, the control elements of the raw material charging device 1 may be adjusted so that this ratio corresponds to the optimum particle size segregation of the sintered raw material layer, for example, the position of the entire device may be moved in the front-rear direction, or the chute angle α may be adjusted. The amount of raw material that passes or does not pass through the slit bar 4 is adjusted by changing the rod spacing of the slit bar 4, changing the length of the run-up plate 3 by sliding the upper plate 3a, etc.

The above measurements may be performed intermittently, but if there is a large change in the particle size distribution of the raw material,
By carrying out measurements continuously and finely adjusting the control elements, stable particle size segregation can be obtained.

〔Effect of the invention〕

As explained above, the present invention measures the height of the coarse raw material that does not pass through the slit bar and the total charging height using a level meter without stopping the operation of the sintering machine, and based on these measured values, the height of the coarse raw material that does not pass through the slit bar and the total charging height are measured. Grain size segregation and carbon segregation are evaluated, and changes in the segregation state can be immediately grasped, making it possible to quickly respond to changes in operation rate and raw material composition, and always charging raw materials with optimal particle size and carbon segregation. becomes. Therefore, it is possible to improve air permeability and combustion efficiency and to make the thermal history of the sintered layer uniform, and it is possible to improve the strength of the sintered ore and the sintering yield.

[Brief explanation of drawings]

Figure 1 is a schematic side view showing an example of a raw material charging device for a DL sintering machine, and Figure 2 is an example of how the distribution of coarse raw materials and fine raw materials within the sintered layer changes over time. This is a drawing. 1... Raw material charging device, 2... Sintered pallet, 3
... Run-up plate, 4 ... Slit bar, 5 ... Lower plate, 6 ... Slit bar rod, 7 ... Deflector chute, 8 ... Cut-off plate, 9 ... Hopper, 10 ... Sintering raw material, 10a
. . . Fine grain raw material, 10b… Coarse grain raw material, 11… Drum feeder, 12, 13… Ultrasonic level meter, α… Shute angle.

Claims (1)

[Claims] 1. The sintering raw material is supplied to a slit bar type raw material charging device that is installed at a constant chute angle with respect to the direction of travel of the sintering pallet, and is charged into the sintering pallet from the tip without passing through the slit bar. The height of the coarse raw material that has passed through the slit bar and the total height of the charged raw material after dropping and charging the fine raw material that has passed through the slit bar onto the coarse raw material are measured using a level meter, and based on the measured values, the height of the raw material that has passed through the slit bar is measured. Calculate the ratio of the fine-grained raw material, evaluate the particle size segregation and carbon segregation of the sintered raw material layer charged to the sintering pallet based on the ratio, and adjust and control the control elements of the raw material charging device. Characteristic raw material charging method for sintering machine.