JPS5918450B2 - Method for producing sintered ore - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing sintered ore, and in particular to a method for producing sintered ore that can produce sintered ore with excellent cold strength and finished product FeO at a high yield. .

As is well known, sintered ore is produced by mixing raw materials for sintering such as iron ore and limestone with coke powder, which is a heat source, and granulating the sintered raw materials by adding moisture in a drum mixer and placing them on a sintering machine bed. It is produced by charging the coke into a furnace to form a raw material layer, igniting it in an ignition furnace while sucking air downward, and firing the coke powder while gradually guiding it from the upper layer to the lower layer.

In general, it is said that it is more effective for improving the quality and productivity of sintered ore if the upper layer of the raw material layer has a larger amount of fuel (coke) than the lower layer.

In addition, generally speaking, the greater the thickness of the raw material layer (called layer thickness), the greater the thickness (called layer thickness).
It is said that the higher the value, the more effective it is in improving the quality of sintered ore.

However, as shown in FIG. 10, the granulation of raw materials for sintering to obtain the raw materials for sintering in the generally practiced sintered ore manufacturing process currently involves iron ore 30, limestone 31, mill scale 32, and converter slag 33. , female side raw materials 35 such as electric furnace slag 34, and return ore 36 (quicklime 31 as a binder may be added in some cases).

) as a sintering raw material 38 and coke powder 3 as a heat source.
9 is mixed and granulated using primary and secondary drum mixers 41 and 42 to obtain a sintered raw material 8.

In addition, charging of the sintering raw material is carried out by transferring the sintering raw material 8 to the raw material supply device 6.
Continuous downward suction sintering machine (DL sintering machine) via bed 9
The raw material layer 7 is continuously formed on the bed 9.

The usual blending ratio of the sintering raw material 38 (excluding quicklime 31 as a binder) is as shown in Table 1, and the particle size distribution of this raw material 38 is as shown in Table 3.

Further, the particle size distribution of the coke powder 39 in the raw material 40 is as shown in Table 5, and the amount is about 3.0 to 3.6%.

Generally, coke powder 39 shown in Table 5 is obtained by crushing coke 44 having the particle size shown in Table 6 using a crusher 43 shown in FIG.

The sintering raw material 8 has an average particle size of 2.5 to 3.5 mm.
The particle size composition is approximately 20 to 30% -1.0.

Moreover, the index showing the air permeability of this raw material 8 is about 50 JPU because there are many -1.0 degrees.

Therefore, in order to ensure a sintered ore production rate of 35T/rrL224H, the layer thickness of the raw material layer 1 is limited to about 500 mm.

However, the air permeability P (JPU) is determined by placing the sintering raw material in a glass container shown in Figure 13 and sucking air at 751 mvt.
Assuming that the suction pressure at this time is S mm A q, the air permeability P is calculated using the following formula.

F: Ventilation volume (tri'7m1n) (75x 10
rri"7m1n) A: Suction area (m2) (4,42
x 10-3 m2) h2 Charge layer thickness (m) (0,3 m) S: Suction pressure (miAq) On the other hand, the feeding device 6 is generally a hopper 1 as shown in Fig. 14.
A device 6 is used which feeds the raw material dropped from the sintering machine via a drum feeder 2 or a belt feeder onto a sintering machine bed 9 via a sloping plate 3.

With such a supply device 6, the coke blending ratio is 3.2%,
Particle size structure; average particle size 3. When the sintering raw material 8 of 27% Omm-1.0mm is charged to a layer thickness of 500 mm, the coke blending ratio of the top layer 100 mm from the layer surface is 3.4%.
, the coke blending ratio in the bottom layer 100 mm is 3.0%, and even though the blending ratio difference is 0.4%, such raw material layer 8 with a layer thickness of 500 mm and a coke blending ratio difference of 0.4% When sintered at a production rate of 35 T/rrL2-24 H, the product yield was 75%, the cold strength (SI) was 87%, and the product F
e06.5%, coke consumption rate 46kg/T-8.

Note that SI is a cold strength index of sintered ore specified in JISM8711 (1977).

The present invention has intensively investigated a manufacturing method that can produce sintered ore with a high yield, particularly in both cold strength (SI) and finished product FeO, compared to the current sintered ore manufacturing method,
In the current production method, we investigated the cold strength of sintered ore in the layer thickness direction and the FeO distribution of the product when the coke powder blending ratio in the blended raw materials was changed, and we investigated the coke strength in the layer thickness direction by increasing the layer thickness. This was done based on the results of a coke blending ratio study in which the cold strength of each layer was made constant by changing the blending ratio.

That is, the gist of the present invention is as follows.

(1) The sintering raw material has a layer thickness of 700 mm or more, and the layer surface (lrF600-7
The coke powder blending ratio gradually decreases in each main part up to the main part of 00 mm, and the difference in coke powder blending ratio between the top layer and the 600 to 700 mm layer part is 1.2% or more, and the
A sintered ore characterized by segregating coke powder so that each main part of 00 mm or more has approximately the same coke blending ratio as the 600 to 70011 trIL layer part, charging it onto a sintering machine bed, and sintering it. manufacturing method.

(2) A sintering raw material with an average particle size of 3.5 to 4.5 mm and a particle size composition of -1 mm 10% or less is sintered with a layer thickness of 700 mm or more, from the top layer 100 mm below the layer surface to 600 mm below the layer surface.
The coke powder blending ratio gradually decreases in each main part up to the main part of 00 mm, and the difference in coke powder blending ratio between the top layer and the 600 to 700 mm layer part is 1.2% or more, and the
The main parts of the 00 and above layers are almost the same as the 600 to 700 layers.
A method for producing sintered ore, which comprises segregating coke powder so as to have a coke powder blending ratio, charging the coke powder onto a sintering machine bed, and sintering it.

(3) The sintering raw material is obtained by granulating the blended raw materials excluding coke powder and has an average particle size of 3.5 to 4.5 mm, -1 mm 10%
It is made by mixing a granulated raw material with the following particle size structure and sized coke of 1 to 3 mm, the layer thickness is 700 to 800 nmH, and the fine coke segregation in the layer thickness direction is caused by passing a pair of sloping plates up and down. A plurality of slit-like openings are formed at predetermined intervals in the sloping direction, directly below the impact position of the sintered raw material on the upper sloping plate that faces each other with a gap in the hopper feeder and receives the sintered raw material from the feeder of the hopper. 3. The method for producing sintered ore according to claim 2, wherein the sintering raw material is supplied to a sintering machine bed using a raw material supplying device provided with an opening.

According to methods (1) to (3), the cold strength (■ value) is 90% or more due to the combination of high-rise thickness and fine coke segregation, and the product is of excellent quality with FeO content of 5.5% or less. Sintered ore is obtained.

In addition, according to method (2), the permeability of the sintered raw material layer on the sintering machine bed is improved, so the productivity can be maintained at the same level as the conventional method in the existing DL sintering machine, and the quality can be improved. Furthermore, in an existing sintering machine, productivity can be increased compared to the conventional method, and the above-mentioned quality improvement effect can be obtained.

Furthermore, according to method (3), it is possible to easily carry out segregated charging of coke breeze with a difference in coke breeze blending ratio of 1.2% using a single raw material supply device, and an existing sintering machine can be extensively modified. Tari, 2
It is possible to achieve high productivity and quality (cold strength, finished product FeO
In both cases, excellent sintered ore can be obtained.

However, the ■ value is a simple measurement value of S■, and is 20 to 3 for sintered ore.
0mmφ to 300f? , 30~50mmφ200
Mix this with a type 1 tester (span 700 mm, diameter 1
50m5φ) and rotated 25 times, the ratio is +15mmφ.

The method of the present invention will be explained in detail below.

The present inventors first charged the sintered raw material 8 obtained by the granulation process shown in FIG.
A raw material layer with a thickness of 1E was obtained and fired (pan tested).

In this case, the coke blending ratio of each important part in the layer thickness direction corresponds to the coke blending ratio of the sintering raw material 8.

Cold strength (■ value) is the quality of fired sintered ore in the thickness direction.
Figures 1a and 1b show representative results for the finished product FeO.

FIG. 1 shows the results of changing the blending ratio of coke powder having the particle size structure shown in Table 5 at three levels: 2.8%, 3.0%, and 3.2%.

The cold strength is the weakest in the upper layer, but has improved in the lower layer.

Although increasing the amount of coke breeze improves the strength of the upper layer, the strength of the lower layer does not improve because it has reached a certain upper limit (work value of about 90%).

On the other hand, in the product FeO, the FeO content is high in the uppermost layer, and is almost constant in the lower layer.

When the coke blending ratio is increased, the product Fe0 distribution line shifts to approximately parallel, and the product FeO increases uniformly.

That is, an increase in the coke blending ratio brings about an effect of improving the average cold strength, but on the contrary, it increases the average finished product FeO.

Decreasing the coke content yields the opposite result.

The heat pattern in the sintered layer is shown in FIG. 2, and the holding time at high temperature becomes longer from the upper layer to the lower layer.

For this reason, the cold strength is low in the upper layer, and the cold strength of the finished product is low.
Because O is rapidly cooled, reoxidation does not proceed to the lower layer, which is high in Fe.
It becomes O.

Conventionally, as a method to eliminate this thermal imbalance in the vertical direction of the raw material layer, the raw materials to be charged to the upper and lower layers of the sintered layer are separately charged, and the upper layer contains a high proportion of coke powder, and the lower layer contains a high proportion of coke powder. A so-called two-stage charging method has been proposed in which a small amount is blended.

However, this method only divides the layer into two layers, upper and lower, and the cold strength required to produce finished sintered ore is maintained over the entire layer thickness, that is, 1.
The coke blending ratio is not appropriate for each detailed layer to ensure a constant value of 90% or more (■ value of 90% is the highest level value regardless of the size of the coke blending ratio).

From the test results shown in Figure 1, in order to achieve a cold hardness value of 90% or higher throughout the entire layer, the coke blending ratio in the upper layer needs to be as high as 3.2% or higher. Finished product F
In order to reduce eO, the coke blending ratio in the lower layer should be increased by 2.
．． It has become clear that it is necessary to keep the coke content to 8% or less, and in short, it is necessary to appropriately adjust the coke blending ratio in the layer thickness direction.

In addition, when there is no segregation of the coke blending ratio in the layer thickness direction, by increasing the lower layer ratio at which the product FeO is approximately constant, in other words, by increasing the layer thickness and relatively increasing the lower layer ratio. It was also found that the average product FeO was reduced.

Therefore, the present inventors next divided the sintering raw material into approximately 100 pieces, and varied the coke blending ratio in the layer thickness direction, thereby achieving a coke blending ratio that would make the cold strength of each layer constant (I value 90%). I asked for

The results are shown in FIG.

The coke content may be 3.6% in the top layer, but 2.4% in the 700 m or less from the top layer.

At this time, the product FeO is 8.0% in the upper layer and 3.5% in the lower layer.
%.

Therefore, if the coke powder distribution is made to maintain the same strength (I value 90%) in each layer, the higher the layer thickness, the more the product FeO
becomes lower.

This relationship is shown in FIG.

As is clear from Figures 3 and 4, the layer thickness is 700+1! I+!
and the coke powder blending ratio gradually decreases in each important part from the top layer to the bottom layer of the raw material layer, and the difference in the coke powder blending ratio between the top layer and the bottom layer is 162% or more. For example, it is possible to secure a single value of 90% or more in each important part, and to obtain an FeO reduction effect of 1.0% compared to the conventional layer thickness of 500 mm.

In addition, when the layer thickness is 7001 tlR or more, the coke powder blending ratio gradually decreases in each important part from the top layer of 100 dragons below the layer surface to the main part of 600 to 7QQgx below the layer surface. If the difference in the coke powder blending ratio from the 700mm layer is 1.2% or more, and each important part 700mm or more below the bed surface is approximately the same as the 600~700mm layer, each It is possible to secure a value of 90% or more in all important parts, and to obtain a FeO reduction effect compared to the conventional layer thickness of 500 mm.

Regarding the method of achieving the optimum coke powder blending ratio as shown in Fig. 3 in the layer thickness direction for a layer thickness of 700 mm or more, for example, 0
70 in 1-stage charging method and 02-stage charging method with 2 or more stages.
The main parts with a diameter of 0 mm or less are charged using the charging device shown in Figure 14.
For the main part up to 700 yn, a pressurized gas jet installed at the bottom of the drum feeder blows high-pressure gas onto the sintering raw material falling from the charging hopper via the drum feeder, as proposed in Japanese Patent Publication No. 51-43003. A method such as charging with a feeding device equipped with a header can be adopted.

By the way, the present applicant has already proposed a raw material supply device that can greatly expand grain size segregation in the layer thickness direction compared to the charging device shown in FIG.

FIG. 15 shows a cross-sectional view of the raw material supply device 11, in which reference numeral 18 is placed at the position of the sloping plate 3 in FIG. 14.

A sloping plate with an opening 19 is provided immediately below the colliding position 22 of the falling material from the drum feeder 2, for example at a distance of 20 to 30 mm, and the sloping plate 18 is provided with an inclination angle θ18=55°.

20 is provided below the sloping plate 18 in parallel with a gap g1, and the sloping plate 18
This is a sloping plate having a length necessary to receive the raw material 8b falling from the opening 19, slide it down, and supply it from the lower end to the pallet 4 (in other words, it has a surface that covers the horizontal projected area of the opening).

Note that the gap go and the gap g1 between the drum feeder 2 and the sloping plate 18 are about 100 mm.

Figure 16 shows the sloping plate 18 with openings in Figure 15.
23 is a ladder-like frame in which a pair of side frames 24 and 24 are connected by a group of connecting rods 25 arranged in parallel at a predetermined pitch.
A slit-like opening 26 with a slit width 81 and a slit length S2 (about the length of the drum feeder 2 body length) is formed between -25.

Then, the upper part 3/11 and the lower part 3/11 of the ladder are installed by covering the entire width with rectangular thin plates 21 and 28, so that a group of rods 25 is installed directly below the collision position 22 of the falling material from the feeder 2. The opening 19 is formed by a group of 26 slit-shaped openings.

In addition, in the sloping plate 18 with an opening shown in FIG. 16, length = 1100 m4 width B = 3000 m town plate 21 length L2 = 300 mm, plate 28 length L28 = 30
The opening length L19 is 500mm, and the slit width 81 formed using the rod 25 of 8.5mmφ is 40mm.

Figure 5 shows the average particle size 3 produced in the granulation process shown in Figure 10.
．． 0 φ-1,011! A raw material layer having a layer thickness of 700 mm was formed using the raw material supplying device 11 shown in FIGS. a, b, c.

d) and coke blending ratio distribution in the layer thickness direction (Fig. 5 e
) is shown.

From FIG. 5C, it can be seen that the number of 3 to 1 fighting particles is small in the lower layer, more in the upper layer, and decreases almost linearly from the upper layer to the lower layer. This is similar to the coke breeze blending characteristics at a fighting layer thickness of 700, which is necessary to ensure a low FeO (90%) and low FeO.

Therefore, as the particle size of coke powder, 100% coke of 1 to 3 yen, preferably 1 to 3 yen, is sized from the coke with the particle size structure shown in Table 5, and such coke powder is attached to other ores, etc. To prevent the particle size from increasing (Fig. 5a,
After the granulation of ore, etc. is completed, the sintering raw material obtained by adding the above-mentioned sized coke is added using the feeding device 11 shown in Fig. 15 and 16 to prevent the characteristics shown in Fig. 70
A raw material layer with a thickness of 0 mm was formed, and the coke blending ratio in the layer thickness direction was investigated.

The results are shown in FIG. The symbols ■ and ■ in FIG. 6 are as shown in the table below.

From now on, by using sized coke of 1 to 3 mm as a sintering raw material made by adding and mixing iron ore etc. after granulation, we will be able to achieve a 1.2% difference in coke blending ratio between the top layer and the bottom layer. It turned out that.

To carry out this method, for example, as shown in FIG. 11, the feeder 6 in FIG. 10 is replaced with the feeder 11 in FIGS. This is sieved with a two-stage sieve 45 of +3 mm and -1 mm, and 1 to 3 grains are supplied to a coke bin 46, and -1 mm
The coke is supplied to the granulator 4T and made into 1-3rIL11L grains, which are also sent to the bin 46, and the +3 is sent to the crusher 43 to be crushed again, and the 1-3mm grain coke from the bin 46 is sent to the secondary DM ( (drum mixer) 42.

As described above, by charging the sintering raw material, which has a layer thickness of 700 mm and is prepared by adding and mixing 1 to 3 times of powdered coke after granulation of ore, etc., using the feeding device 17 shown in FIGS. 15 and 16, By ensuring a sufficient coke blending ratio difference of 1.2%, cold strength can be maintained and the FeO content of the finished product can be reduced.

According to the results of the present inventors' experiments described below, a layer thickness of 80
Almost the same effect as a layer thickness of 11,700 mm could be obtained up to 0 mm.

Furthermore, in the gas injection type charging device disclosed in Japanese Patent Publication No. 51-43003, a layer thickness of 700 mm can be achieved by adding sized coke of 1 to 3 mm to the raw material after granulation as a sintering raw material. We were able to obtain a difference in coke blending ratio of 1.2%.

As described above, when the layer thickness is increased from 500 mm to 700 m71 or more, the productivity (rate) decreases.

Figure 7 shows this trend.

That is, when the layer thickness is increased, the airflow resistance increases, which reduces the flow rate of air passing through the sintering bed, and as a result, the sintering progress is delayed and the productivity (rate) is reduced.

In order to cope with this, increasing the negative pressure of the blower to strengthen the suction power will maintain productivity (rate), but this will increase electricity costs and costs.

The inventors of the present invention have developed the properties of sintered raw materials in the process of conducting various studies on how to reduce the power cost to a conventional thick layer, keep the productivity (rate) at the same level as before, and preferably improve the quality of sintered ore. We focused on

Figure 8 shows the blended raw materials 40 in the granulation process in Figure 10.
The DM granulated powder particle size (dashed line) and the DMM post-granule particle size (dotted chain line) are shown.

In this way, although the particle size distribution of the sintered raw material 8 after granulation with DM has decreased on the fine grain side, there are still 2 particles with a diameter of 1 mm or less.
7%, and these 27% of 1 mm particles inhibit the air permeability of the raw material layer, and the index showing the air permeability of this raw material is also 50 JPU.
and low.

Therefore, by using the above-mentioned blended raw material 40, adding about 1.0% of a binder such as bentonite during granulation, and changing the granulation machine from a drum mixer to a pan pelletizer (hereinafter abbreviated as PP), the granulation was strengthened. I did it.

The sintered raw material 8 whose distribution is also indicated by a solid line in FIG. 8 shows the result of PP granulation, and the PP granulation reduces the φ particles to about 10% and the average particle size from 3.0 mm to 4.2 mm. At the same time as giving
The particle size distribution is narrowed to a narrow range, resulting in an air permeability index of 80JP.
Improved with U.

In addition, in the granulation system shown in Figure 10, bentonite is
and when adding 1.0%, the average particle size is 3.5 and 4.5
We obtained a sintered raw material with a thickness of 10% or less.

In addition, when granulating with PP, the PP granulation time is 3.0,
6.0 and 9.0 minutes, the average particle size was 3.5°4.
2. At 4.5 mm, it was possible to obtain a raw material with a thickness of less than 10%.

In addition, sintering raw material 3 obtained by removing coke from blended raw material 40
Even if it is 8, the particle size before granulation is the same as the particle size of the raw material 40, so the particle size after granulation after granulation reinforcement and its air permeability index are also the same.

Therefore, it goes without saying that the sintering raw material 48 made by adding and mixing 1 to 3 times of sized coke at a rate of about 3% to this granulated material can also ensure 80 JPU.

FIG. 9 is a diagram showing the relationship between the air permeability index JPU and productivity (rate).

The same productivity as a 50 JPU raw material with a layer thickness of 500 mm is a layer thickness of 80 mm.
In the case of 0mm, it can be seen that 80J PU raw material is sufficient.

It can also be seen that in the case of a layer thickness of 700 mvt, the productivity is improved by using an 80 JPU raw material as compared to a 500 mvt or 50 JPU raw material.

In this way, the layer thickness can be increased while maintaining the productivity (rate) or increasing the productivity (rate).

FIG. 12 shows the supply device 11 of FIGS. 15 and 16 with a layer thickness of 7.
In the granulation and charging system to obtain optimal coke segregation for 00 to 800 Yen, a pan pelletizer 49 is used to strengthen the granulation, and the primary DM 41 in Fig. 11 is used as a sized coke 46.
This figure shows an optimal granulation/charging system that can maintain or improve productivity and improve the quality of sintered ore by distributing it between the addition positions.

Furthermore, this system requires only one supply device, which is advantageous in terms of equipment costs.

Example In order to obtain sintered ore having the components shown in Table 2, mixed raw materials having the particle size distribution shown in Table 3 were obtained at the mixing ratio shown in Table 1.

When this blended raw material is sintered using the sintering machine shown in Table 4, the flow of granulation, mixing, and charging (charging equipment used in Figures 15 and 16) shown in Figures 11 and 12 (Example 1) and 2)
The sintered ore was sintered.

In addition, as a comparative example, sintered ore was sintered according to the mixing granulation and charging flow shown in FIG. 10 (the apparatus shown in FIG. 14 was used).

Table 7 shows the particle size and blending amount of coke powder in Comparative Example and Examples 1 and 2, Table 8 shows the operating conditions, and Table 9 shows the results of granulation and charging operations.

Table 10 shows the operational results.

[Brief explanation of the drawing]

Figure 1 a and b show coke blending ratio, 1 value and finished product FeO
Figure 2 is an explanatory diagram of the relationship between the
The figure is an explanatory diagram of the coke blending ratio distribution where the cold strength is constant in the layer thickness direction and the FeO distribution at that time. Figure 4 is an explanation of the relationship between the layer thickness and FeO in the case of the coke blending ratio distribution of Figure 3. Figure 5a. b, c, d, and e are explanatory diagrams of particle size and coke segregation when the sintered raw material produced in the process of Figure 10 is charged with the raw material supply device of Figure 15.16, and Figure 6 is an illustration of the conventional method and Figure 1 is an illustration of the relationship between layer thickness and productivity; Figure 8 is an illustration of particle size distribution; Figure 9 is an illustration of the relationship between permeability and productivity; Figure 10 is an illustration of the relationship between permeability and productivity. The figure is an explanatory diagram of the conventional mixed granulation and charging process, Figure 1L12 is an explanatory diagram of the granulation and mixed charging process of the present invention, and Figure 13 is an explanatory diagram of the air permeability measurement method.
Fig. 14 is an explanatory diagram of a conventional raw material supply device, Fig. 15, 1
FIG. 6 is an explanatory diagram of the raw material supply device used in the method of the present invention. 1...Hopper, 1a...Hopper gate, 2...Drum feeder, 3...
・Sloping plate, 4...Sintering machine pallet, 5...Grate bar, 6...Raw material supply device, 1...Charging material layer (sintering machine pallet) formation material layer),
8... Sintering raw material, 9... Sintering machine bed, 10... Ignition furnace, 11... Raw material supply device, 18...・Sloping plate with opening,
19... Opening, 20... Sloping plate, 22... Falling material collision position, 23...
...Ladder-shaped frame, 24...Side frame, 25...Connecting rod, 26...
・Slit-shaped opening, 21...Top plate, 2
8... lower plate, 30... iron ore, 31... limestone, 32... mill scale, 33... converter slag, 34... Electric furnace slag, 35... Cutting raw material, 36... Return ore, 31... Binder (quicklime), 38...
... Raw materials for sintering, 39 ... Coke powder, 4
0...Blended raw materials, 41...Drum mixer, 42...Drum mixer, 43...
...Crusher, 44...Raw material coke powder, 45.
...2nd section a 46"-coke bin, 4T
...Pelletizer, 48 ...Sintering raw material, 49
...Pan pelletizer.

Claims (1)

[Claims] 1. A sintered raw material with a layer thickness of 700 mm or more and 10 mm below the surface of the layer.
The coke powder blending ratio gradually decreases in each layer from the top layer at 0 to 600 to 700 below the surface of the layer.
And the difference in coke powder blending ratio between the top layer and the 600 to 700 fighting layer is 1.2% or more, and each layer 700 mm or more below the layer surface has approximately the same coke powder blending ratio as the 600 to 700 mm layer. A method for producing sintered ore, which comprises segregating coke powder, charging it onto a sintering machine bed, and sintering it. 2 Sintering raw material with an average particle size of 3.5 to 4.5 mm and a particle size composition of 10% or less between -1 and 600 to 700 r below the layer surface from the top layer 100 mm below the layer surface with a layer thickness of 700 mm or more.
The coke powder blending ratio gradually decreases in each layer up to the It11L layer, and the difference in coke powder blending ratio between the top layer and the 600 to 700 layer is 1.2% or more, and the coke powder blending ratio is 70% below the layer surface.
Each layer above 01nrIL is 600 to 7001nrIL
1. A method for producing sintered ore, which comprises segregating coke powder so that it has approximately the same blending ratio of coke powder as the layer, charging it onto a sintering machine bed, and sintering it. 3 The sintering raw materials are granulated raw materials with an average particle size of 3.5 to 4.5, obtained by granulating the blended raw materials excluding coke powder, and a particle size composition of -1m10% or less, and sized coke of 1 to 3 mm. The layer thickness is 700 to 800 mmH, and the segregation of fine coke in the layer thickness direction is achieved by installing a pair of sloping plates facing each other with a gap in the vertical direction, and feeding the sintered raw material from the feeder of the hopper. A raw material supply device is provided with a plurality of slit-shaped openings formed at predetermined intervals in the sloping direction directly below the impact position of the falling sintered raw material on the upper sloping plate. The method for producing sintered ore according to claim 2, characterized in that the method is achieved by supplying the sintered ore to