JPS5952693B2 - DL sintering method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention utilizes a moving grate type Dwight Lloyd type (hereinafter referred to as DL).
The purpose is to provide a sintering method that prevents uneven sintering of sintered ore and effectively improves its quality and productivity. It is in.

As is well known, in DL sintering equipment, iron ore, lime,
The sintering raw material, which is made by kneading coke or other powder with an appropriate moisture content and forming pseudo-granules, is charged into a pallet, then the surface layer is ignited, and an exhaust fan is used to suck it downward. At the same time, sintering is performed by moving pallets to produce sintered ore.

By the way, in the production of the sintered ore, the method of charging the sintered raw material into the pallet is an important factor for improving the production efficiency and quality. As an effective charging method, for example, using a drum feeder so that the particle size distribution charged on the pallet is in the height direction, that is, between the upper and lower layers, the lower layer is coarse particles and the upper layer is fine particles. Technological means have heretofore been known in which a sloping chute and/or a pressurized gas injection nozzle is arranged in the lower part, and the sintering raw material is charged while being rolled on the sloping chute or classified by wind.

However, in the conventional particle size distribution adjustment, that is, charging control that is performed while causing particle size segregation, there is no means to reliably detect the particle size segregation state, so it is difficult to grasp the particle size segregation state during operation. For example, problems such as not being able to obtain the desired grain size segregation, or the surface layer becoming too fine and causing excessive segregation, resulting in poor air permeability and deterioration in the quality of sintered ore, often occur. Even in such cases, it is extremely difficult to take prompt and appropriate measures such as changing the charging control using the conventional method.

The present invention was made as a result of repeated various experimental studies in order to proactively solve the above-mentioned conventional problems. Based on the correlation that exists between the two, the moisture segregation degree is determined from the average moisture content and surface moisture obtained by actually measuring the sintered raw material, and then the carbon content segregation degree is calculated from the moisture segregation degree, and the carbon content segregation degree is calculated from the moisture segregation degree. When charging the sintering raw material into the pallet so that the degree of segregation is 1.05 to 2.0, the distribution of carbon (hereinafter simply referred to as C) in the raw material layer in the height direction and/or width direction is checked. It is characterized by conditioning and sintering.

Hereinafter, the present invention will be described in detail based on Examples.

Now, as a result of repeated various experimental studies as described above, the present inventors have found that the particle size segregation of the sintered raw material charged into the pallet is closely related to the distribution state of C in the raw material layer, that is, the C segregation. We have obtained new knowledge that the C segregation has a correlation with the moisture segregation of the sintering raw material before firing.

FIGS. 1, 2, and 3 show the results of an experiment based on the present invention. In the DL sintering equipment shown in FIG. This study investigated the corresponding C segregation state and water segregation state, and the height direction of the raw material layer was divided into seven parts between the surface and the bottom (the top layer is the surface layer, which will be described later, and the other parts are The average particle size of the sintering raw material at each point is shown on the vertical axis (Fig. 1).
, C concentration (Fig. 2), and water content (Fig. 3) are shown on the horizontal axis.

From FIGS. 1, 2, and 3, as the pressure gas injection volume increases, the particle size segregation naturally increases, and along with this,
Although the quantitative correlation is not clear, C segregation and moisture segregation occur based on a certain pattern, and there is a particularly close relationship between C segregation and moisture segregation. Content and surface moisture (In the present invention, the surface C content and surface moisture refer to the average C content and moisture in the surface layer at a depth of approximately 10 to 30 mm from the surface of the raw material layer.

), it was confirmed that the C segregation state, water segregation state, etc. in the height direction of the raw material layer can be accurately estimated, and the particle size segregation state can also be almost certainly estimated and understood.

FIG. 4 is a partial cross-sectional view showing one embodiment of the DL sintering equipment feed section for explaining the present invention.

In FIG. 4, 1 is a granulation drum, and 2 is a sintered raw material that has been made into pseudo-granule agglomerates in the granulation drum 1.

The sintered raw material 2 discharged from the granulation drum 1 is supplied to a hopper 5 via a charging conveyor 3, an oscillating conveyor 4, etc., and is stored once in a drum feeder 6.
It is cut out in fixed amounts and loaded into pallet I-7.

Further, in this embodiment, a sloping chute 8 and a pressure gas injection nozzle 9 are provided between the drum feeder 6 and the pallet 7, and the sintered raw material 2 falling from the drum feeder 6 is transferred on the sloping chute 8.
It also made it possible to charge while performing wind classification using pressurized gas.

Furthermore, in FIG. 4, 10 is an ignition furnace.

Now, FIG. 5 shows the moisture segregation and carbon content of the sintered raw material 2 before firing in the DL sintering equipment of FIG. This shows the results of an experiment investigating the relationship between moisture segregation and water segregation, which is determined by the ratio of the average moisture Psi of the sintering raw material 2 to the surface moisture PS2, CPs□/Ps.
□) (hereinafter referred to as water segregation degree The C segregation degree (hereinafter referred to as y) is expressed on the vertical axis, and the correlation therebetween was investigated.

In this experimental example, the average water content Psi is measured at the middle part of the charging conveyor 3, and the surface water content PS2 is measured at the sintered raw material 2 on the pallet 7 at the middle part between the drum feeder 6 and the ignition furnace 10.
The moisture content was detected using the dry weight method, and the average C content was calculated from the actual blending ratio of sintering raw material 2. Samples were taken on the pallet 7 in the middle between the feeder 6 and the ignition furnace 10, and the C content was measured.

From FIG. 5, it is clear that irrespective of the difference in the average moisture content of the sintering raw material 2, the degree of water segregation and the degree of C segregation have a correlation shown in the following equation (1).

However, y: Carbon content segregation degree (C segregation degree) C5□: Average carbon content of sintered raw material C5゜: Carbon content on the surface of sintered raw material on the pallet before reaching the ignition furnace X: Moisture segregation degree P5, : Average moisture content P of the sintered raw material in any process after the granulation drum and before reaching the ignition furnace, 2: Surface moisture of the sintered raw material on the pallet before reaching the ignition furnace a, l): Depending on raw material conditions, equipment conditions, etc. Constants to be determined (in this example, a is 3.66 and b is -2,66, so equation (1) is V
=3,66X-2,66.

) and the sloping chute 8 or injection nozzle 9
The constants a and l) are determined in advance according to the charging equipment conditions or blended raw material conditions, etc., and the average moisture content P5□ of the sintered raw material 2 charged to the pallet 7 is calculated from the granulation drum 1.
Any process from before reaching the ignition furnace 10, such as on the charging conveyor 3, the oscillating conveyor 4, or when falling from the hopper 5 or the drum feeder 6, or in some cases after being charged to the pallet 7. The surface moisture P5□ was measured at approximately the center of the layer, and the surface moisture P5
It is actually measured on the pallet 7 before reaching 0, that is, between the drum feeder 6 and the ignition furnace 10 after C segregation has occurred, and the ratio, that is, the degree of moisture segregation X is determined. X
By substituting y into the equation (1), it is possible to calculate the C segregation degree y of the sintering raw material.

In addition, if necessary, the average C content of the sintered raw material 2 can be calculated by, for example, actually measuring the cut-out amount of the blended raw material and its blending ratio, or by sampling the sintered raw material 2 and actually measuring it. Accordingly, it is possible to easily estimate the surface C content of the sintered raw material 2 from the correlation of equation (1).

Note that the detection of the average moisture Psi and surface moisture Ps2 is as follows:
Of course, there is no problem in sampling and measuring the corresponding sintered raw materials 2 as in the above embodiment, but if necessary, it is possible to make effective use of an infrared moisture meter or a neutron moisture meter, etc. At multiple measurement points in the width direction of 7,
However, it is also possible to perform the detection continuously during operation or at every set period.

FIG. 4 shows an embodiment of a moisture detection device 11 using the infrared moisture meter.

That is, the middle part of the charging conveyor 3 and the drum feeder 6
and detection ends 11a1 and 11 at the middle part of the ignition furnace 10, respectively.
cut-off plate 11C on the charging conveyor 3 where C segregation has not occurred at the detection end 11a1.
The detection end 11a2 detects moisture immediately after smoothing the surface of the raw material layer and exposing a new surface, and the detection end 11a2 detects moisture in the surface layer of the raw material on the pallet 7 after C segregation has occurred. The detected value was input as a detection signal to the moisture detectors 11b1 and 11b2 and displayed.

Further, in this embodiment, the detection signals from the detection ends 11a1 and 11a2 are inputted to the arithmetic and control unit 12 via the moisture detectors 11b1[deg.]1b2.

If the arithmetic and control unit 12 is pre-stored with the formula (1) and is provided with a function of calculating the average C content, the detection signals from the detection ends 11a1 and 11a2 and the sintering , the blending ratio of sample 2 (the blending ratio may be determined using either the cutting results of each blended raw material or the cutting command signal).

), it is possible to not only calculate the degree of C segregation y but also automatically calculate the surface C content as needed, and furthermore, the arithmetic and control unit 12 can perform various charging controls as described below. If this function is provided, it will be possible to calculate the C segregation degree y and, based on the calculation result, to quickly and accurately control charging as necessary so that the optimum charging condition is always maintained. It is also possible to have this done automatically, which is very effective.

Next, Table 1 below shows the results of an investigation into the relationship between productivity and sintered ore strength when sintered ore was produced by varying the C segregation degree y.

In Table 1, when the C segregation degree y is 1, there is no C segregation at all, and the surface C content becomes higher than the average C content, and when C segregation occurs, the C segregation degree gradually decreases from 1. However, if the C segregation degree y is less than 1.05, the C segregation is not sufficient and the productivity is extremely low.

However, when the value is 1.05 or more, both productivity and strength are significantly improved, and this effect is particularly significant in the range of 1.1 to 1.5, indicating that C segregation has an important influence on sintered ore production. What is being provided is clearly shown.

However, if the C segregation degree y exceeds 2.0, there will be excessive segregation, and the surface of the sintered layer will be in an over-molten state, which will worsen the permeability, resulting in a decrease in productivity, and the strength of the sintered ore will also decrease. It was confirmed that the upper layer became amorphous and became brittle, while the lower layer suffered from poor sintering due to lack of heat, which adversely affected its quality.

This is the reason why the C segregation degree y is limited to a range of 1.05 to 2.0 in the present invention.

By the way, as a specific means for charging the sintering raw material 2 into the pallet 7 so that the C segregation degree y falls within the predetermined range, first, as shown in FIG. A nozzle 9 is installed to spray pressurized gas such as air, inert gas, or water vapor adjusted to an appropriate wind speed onto the sintered raw material 2 falling from the sloping chute 8 or the drum feeder 6 onto the pallet 7, resulting in wind classification. By charging while carrying out the above steps, it is possible to produce the desired C segregation.

FIG. 6 shows the injection nozzle 9 in the charging equipment equipped with the sloping chute 8 and the injection nozzle 9 shown in FIG.
This is a chart showing the results of an experiment in which the relationship between the air volume and the surface C content was investigated by injecting more air. The layer height is 450mm,
The supply amount of the sintering raw material 2 is 300 T/H.

From FIG. 6, it has been found that the surface C content can be arbitrarily adjusted by varying the amount of air injected from the injection nozzle 9, that is, the speed of the impinging wind against the falling raw material layer. By adjusting the surface C content, it becomes possible to appropriately adjust the C segregation state in the height direction of the raw material layer as described above.

FIG. 7 is a plan layout diagram showing an embodiment of a pressure gas injection device in which the air volume can be easily adjusted and the air volume can be adjusted in the width direction of the pallet 7.

In FIG. 7, 13 is a pressure gas supply pipe, and 14 is a header.

The injection nozzle 9a is divided into a plurality of pieces in the width direction of the pallet l-7, and the divided injection nozzle 9a is connected to the air volume control valve 15.
It is connected to the header 14 via.

Thus, for example, a plurality of detection ends 1 are arranged in the width direction of the pallet 7.
The surface moisture P5 is detected by the moisture detection device 11 having 1a2.
° is detected, and as a result, if the surface C content is not constant in the width direction of the pallet 7 and has variations,
By controlling the opening degree of the air volume control valve 15 according to the variation, the air volume of the pressurized gas can be arbitrarily adjusted in the width direction of the pallet 7, and not only in the height direction in the raw material layer.
It is also possible to appropriately control C segregation in the width direction.

In the embodiment shown in FIG. 7, the injection nozzles 9a1 at both ends
The reason for changing the injection direction is when the C segregation near both ends of the pallet 7 is not sufficient due to the both end effect of the free jet of pressurized gas, or when there is significant dust generation outside the pallet 7. For example, the injection nozzle 9
If a1 and the air volume control valve 15 are connected via the telescopic pipe 16, the direction can be changed arbitrarily and easily.

Of course, if there is no particular need to adjust C segregation in the width direction of the pallet 7, the structure of the injection nozzle 9 may be changed so that, for example, the air velocity is uniform in the width direction, or the central part and both ends inject pressurized gas at a set air velocity ratio. Continuous sleeve I.
Of course, it is also possible to use something as simple as a shaped opening or a nozzle at regular intervals.

In some cases, the injection nozzle 9 may not be installed and, for example, the slope angle of the sloping chute 8 may be simply changed arbitrarily, or a large number of rotating rollers may be arranged in the same shape as the sloping chute 8, although not shown. The rotating roller is rotated in the descending direction of the sintering raw material 2 or in the opposite direction to the descending direction, or the arrangement pitch of the rotating roller is changed in the vertical direction to increase the gap between the outer surface of each adjacent roller. It is quite possible to cause C segregation by making the upper part narrower and the lower part wider.

Therefore, depending on the charging conditions of the sintering raw material 2 and the equipment conditions, etc., the sloping chute 8 corresponding to FIGS. 2 and 5, the inclination angle of the outer surface of the rotating roller, or the rotation Roller rotation speed, arrangement pitch, etc., change rate of surface C content, and C in the height direction of the raw material layer
In addition to investigating and understanding the segregation state etc. in advance, the above (
1) The present invention can be applied effectively by determining the constants a and l) in the equation.

However, in the experience of the present inventors, the method of installing and utilizing the sloping shoes = 1, 8 and the jet nozzle 9a as shown in the above-mentioned Fig. 3 and Fig. This adjustment can be carried out arbitrarily and accurately in the width direction and the width direction, the adjustment range is extremely wide, and the control is easy, so automation as described above can be performed easily and is very effective.

As described in detail above, the present invention is based on the new finding that there is a correlation shown in equation (1) between the moisture segregation and C segregation of the sintered raw material 2 before firing. The C segregation degree y is calculated and estimated by actually measuring the average moisture P5□ and the surface moisture P5゜, and the C segregation degree y is set within the range of 1.05 to 2.0 or 1.05 to 2.0. The sintering raw material is sintered by adjusting the amount of pressurized gas jet or the inclination angle of the sloping chute 8 so that the sintering material is sintered while adjusting the C segregation in the raw material layer, that is, the distribution of C in the height direction and/or width direction. 2, and then sintered.

As described above, according to the present invention, optimal charging control of the sintered raw material 2 can be carried out continuously during operation or as needed, quickly and appropriately, so that production of sintered ore can be achieved. The efficiency and quality were significantly improved, and in addition, the ignitability of the surface layer of the raw material was improved, so the fuel consumption in the ignition furnace 10 was significantly reduced, and the energy saving effect was also extremely large.

As described above, the industrial and practical effects of the present invention are very large.

[Brief explanation of the drawing]

Each figure shows an example of the present invention. Figure 1 is a diagram showing the particle size segregation state in an example in which the sintering raw material is charged while injecting pressurized gas, and Figure 2 is a diagram showing the corresponding C segregation state. A diagram showing the state, Figure 3 is a diagram showing the water segregation state,
Figure 4 is a partial sectional view showing an example of the ore feed section of DL sintering equipment, Figure 5 is a chart showing the results of investigating the correlation between moisture segregation and C segregation, and Figure 6 is a diagram showing the results of an investigation of the correlation between water segregation and C segregation. A diagram showing the relationship between air volume and surface C content, and FIG. 7 is a plan layout diagram showing one embodiment of the pressure gas injection device. 1... Granulation drum, 2... Sintering raw material,
3...Charging conveyor, 4...Oscillating conveyor, 5...Hopper, 6...
...Drum feeder, 7...Pallet, 8
・・・・・・Sloping shoot, 9°9a, 9a'
... Pressure gas injection nozzle, 10 ... Ignition furnace, 11 ... Moisture detection device, 12 ...
- Arithmetic control device, 13... Pressure gas supply pipe, 1
4... Header, 15... Air volume control valve, 16... Telescopic pipe.

Claims (1)

[Claims] In the IDL sintering method, the sintering process is performed based on the correlation shown in the following equation (1) between the moisture segregation degree of the sintering raw material before firing and the carbon content segregation degree. The moisture segregation degree (Ps□/PS,) is determined from the average moisture content Psi and the surface moisture Ps□ obtained by actually measuring the raw material, and then the moisture segregation degree (S
Calculate the carbon content segregation degree y from s□/Ps,) so that the carbon content segregation degree y is 1.05 to 2.0.
A DL sintering method characterized by adjusting the distribution of carbon in the height direction and/or width direction in the raw material layer when charging the sintering raw material into a pallet, and sintering the raw material. However, y: Carbon content segregation degree C5□: Average carbon content of the sintered raw material C5□: Carbon content on the surface of the sintered raw material on the pallet before reaching the ignition furnace P5: After the granulation drum and before reaching the ignition furnace Average moisture content of the sintered raw material in any process up to P8□: Surface moisture of the sintered raw material on the pallet before reaching the ignition furnace a, l): Constant determined by raw material conditions, equipment conditions, etc.