JPH10330854A - Production of sintered ore - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a producing method of a sintered ore which improves the productivity of the yield, etc., of the sintered ore by making blending ratio of the solid combustible material existing on the upper layer part more than that on a lower layer part in the sintering raw material filling layer to raise the strength of the sintered ore. SOLUTION: At the time of laying the sintering raw material 11 onto a shifting pallet 1 from a hopper 4 through a chute 8, the solid combustible material 15 is mixed into the sintering raw material 11 at the position where the sintering raw material 11 slides on the chute 8 or is on the way of dropping from the chute 8. The blending ratio of the solid combustion material existing on the upper layer part 3 of the sintering raw material filling layer laid on the shifting pallet 1 is more than the lower layer part 2 to execute the operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a sintered ore which is a main iron ore raw material for iron making.
The present invention relates to a method for producing a sintered ore in which productivity is improved by uniformly increasing sintering strength and improving yield.

[0002]

2. Description of the Related Art Raw materials for sinter are mainly iron oxide raw materials such as fine ore or fine ore, or iron-containing raw materials (mill scale, blast furnace dust, converter dust) generated in an ironworks. It is a common practice to mix limestone or quartzite as an auxiliary material, add coke breeze as a solid combustible material, and sinter it.

FIG. 12 is a schematic explanatory view showing the outline of a typical Dwyroid (DL) type sintering machine as a sintering machine, in which 21 is a moving pallet, 22a is a drum mixer, and 23 is an ignition A burner, 24 indicates a blower, and 25a indicates a hopper. (The system of the hopper 25b and the drum mixer 22b is an embodiment described in JP-A-5-98358 described later.) When sintering is produced by this sintering machine, the sintered product ore that has been sintered is used as a bedding for 20 to 30 minutes.
The main raw material, the auxiliary raw material, and the solid combustible as described above are mounted on the movable pallet 1 on which the mm is mounted. More specifically, the main raw material, the auxiliary raw material, and the solid combustibles respectively stored in the hopper 25a are taken out, and further added with water, mixed and granulated by the drum mixer 22a, and formed into pseudo-particles of the sintered ore. The raw materials are spread in layers on the moving pallet 1 to a thickness of 300 to 600 mm. Then, the solid burnable substance (usually using coke breeze) existing in the upper layer of the raw material layer is ignited by the ignition burner 23 installed immediately after the raw material charging position. Air flows in the raw material layers spread in layers by suction of air from above to below by the blower 24, whereby the combustion position gradually burns from the upper layer portion to the lower combustible material. Due to the heat generated by combustion of the combustible material, a part of the raw material filling is melted, and then cooled, whereby the raw material particles are bonded to each other, and then crushed by a crusher (not shown) to about 50 mm or less,
It is sieved and adjusted to a particle size that is easy to use in the blast furnace in the next step.

[0004] As a method of increasing the productivity of the method for producing a sintered ore, there are a method of improving the sintering speed by improving the permeability of a sintered bed, and a method of increasing the sintering strength to reduce the amount of fine powder generated during crushing. A method of reducing the yield to improve the yield is roughly classified into two methods. As the above-mentioned method, specifically, a method of blending an appropriate amount of small lump ore, slag, etc. of 8 to 15 mm (Japanese Patent Laid-Open No. 1-2
05038) and a method of adding molasses to raw ores to sufficiently promote granulation (JP-A-58-107428).

On the other hand, as the above-mentioned method, a method of charging a high-melting ore into the upper part of the pallet and a low-melting ore into the lower part thereof (JP-A-62-130229), (See Japanese Patent Application Laid-Open No. 62-60829), a method in which the flow rate of air passing through the sintered layer is measured with an anemometer, and the flow rate in the width direction is made uniform (Japanese Patent Application Laid-Open No. 62-60829). No. 61-250120) and the like.

[0006] The yield of the product sintered ore is affected by various factors such as the amount of heat supplied, the amount of bonded slag and its strength and porosity. Among the factors, the effect of the embrittlement layer existing in the upper part of the sintering material filling layer is the largest,
The yield of product sinter is particularly low. This embrittlement layer is assumed to be present in the upper part of the depth portion from the outermost layer of the sintering raw material filling layer to 30 to 50 mm, and the amount of molten slag required for bonding of the sintered ore is greater than other parts. The packing layer is extremely small and brittle. The reason why the embrittlement layer is formed is considered as follows. That is, in the sintering step, air at about room temperature is inevitably sucked from above the sintering raw material packed layer. For this reason, in the upper part of this sintering raw material filling layer,
Before the ore is heated to the high temperature required for melting the slag-making component, the combustion of the coke in the sintering material packed bed (bed) ends. As a result, in the upper part of the sintering raw material-filled layer, the amount of molten slag required for bonding of the sintered ore tends to be insufficient, and the portion where the amount of molten slag is insufficient is the embrittlement layer. Becomes

The tendency of the yield of the upper part of the sintering raw material packed layer to decrease due to the presence of the embrittlement layer is due to the recent decrease in high-quality iron ore and the accompanying large amount of low-cost iron ore raw materials such as highly crystalline water ore. Depending on the situation of use, it is greatly enhanced. However, each of the above prior arts has no effect in eliminating or reducing the embrittlement layer itself, and cannot prevent a reduction in the yield of the upper layer portion of the sintering raw material filling layer.

Therefore, as a method of eliminating the embrittlement layer and improving the yield of the upper layer of the sintering raw material-filled layer, the solid combustible (coke) particle size is reduced, By segregating the upper layer of
Increasing the coke concentration in the upper layer is disclosed in "Materials and Process" (Vol. 13, 1990, p. 964).
However, although this method is certainly effective in eliminating the embrittlement layer, the controllability of the segregation charging is poor, and the fine coke concentration in only the uppermost layer of the sintering bed can be increased. However, the fine coke concentration increased in a wide layer thickness direction including the lower layer portion, and the packed layer was excessively melted over a wide range, and the expected effect was not obtained. In addition, fine coke may adhere to the raw material having a large particle when the raw material is charged, and may be charged into a lower portion of the sintering bed, which also causes a deterioration in controllability.

For this reason, the coke particle size is made relatively coarse, and the coarse coke raw material is segregated and charged into the upper layer, thereby increasing the coke concentration in the upper layer and increasing the productivity of the sintered ore. The present inventors have proposed a technique for
This is proposed by Japanese Patent Publication No. 5-98358. This method
50% of solid combustibles existing at a depth of 30 to 50 mm from the outermost layer of the sintering material packed layer placed on a moving pallet
The above is adjusted while adjusting the particle size distribution so as to be occupied by those having a particle diameter of 1 to 3 mm, and the compounding amount of the solid combustibles present in the depth portion is determined by calculating the average compounding amount of the solid combustible materials present in the deeper portion. It is intended to be adjusted to 1.08 to 1.42 times.

In this prior art, a new solid combustible material is sintered in order to increase the amount of solid combustible material in the upper part (the depth from the outermost layer to 30 to 100 mm) of the sintering raw material packed layer. As shown in FIG. 12, the method of compounding the raw materials is as follows: a separate hopper 25 between a normal drum feeder 22 and an ignition burner 23, a mixer 22 for mixing ore and coke.
a, a feeder 26, and the like are installed, and solid combustibles are deposited from the upper layer of the sintering raw material packed layer placed on the moving pallet. Further, in this embodiment, the experimentally adjusted amount of the solid combustible material in the sintering raw material is adjusted to the optimum blending amount, and the flammable material is placed on the upper layer of the sintering raw material filling layer and used. Further, another Japanese Patent Application Laid-Open No. 61-127727 discloses a method of controlling the distribution of a target solid combustible by directly blowing a solid combustible through a nozzle together with air into a sintering bed before ignition of a sintering raw material. Is also disclosed.

[0011]

The most important thing in charging and blending a solid combustible material into the sintering raw material packed layer is that the solid combustible material is charged and blended in the sintering raw material packed layer. This is how to uniformly distribute the solid combustible material to the desired layer thickness (the depth from the outermost layer to 30 to 100 mm).
However, all of these conventional methods of supplying solid combustibles have poor controllability for uniformly distributing solid combustibles across the width of a sintering raw material packed layer placed on a moving pallet. However, there is a problem that the target distribution state cannot be achieved.

In particular, in the supply method of blowing through a nozzle as disclosed in JP-A-61-227827, solid combustibles cannot be supplied to portions other than the sintering material layer near the blowing position of the nozzle. The material can be supplied only locally, for example, exhibiting a streak-like segregation layer in the width direction of the sintering raw material filling layer. Further, there is a problem that the state of filling (lamination) of the sintering raw material that falls from the chute onto the moving pallet is disturbed by the presence of the nozzle or the air flow to be sent. And, in this state, firing unevenness rather occurs, which lowers the strength of the sintered ore, impairs productivity, and deteriorates the unit fuel consumption.

In the supply method disclosed in FIG. 12 of Japanese Patent Application Laid-Open No. 5-98358, since the solid combustible is supplied onto the sintering material packed layer already deposited, the sintering material and the solid flammable material are supplied. The materials are not sufficiently mixed, and a layer of only solid combustibles is formed on the outermost surface. For this reason, only solid combustibles are burned and locally melted, which tends to cause new problems such as impairing air permeability. Further, since the solid combustible material supply device is provided in a separate system, there is a problem that the cost of the device itself is high.

That is, in order to eliminate the embrittlement layer and improve the yield of the sintered ore, the solid combustible material such as coke is segregated in the upper layer of the sintering raw material packed layer. Although it is effective to increase the concentration of solid combustibles, there has been no method to ensure this,
It is a fact that it could not be applied to the actual method for producing sinter.

The present invention has been made in view of these problems of the prior art, and has been found to be 30 to 100 m from the upper layer, particularly the outermost layer, of the sintering material packed layer.
It is possible to operate with a greater amount of solid combustibles present at depths up to m than the amount of solid combustibles present at deeper depths, in other words, newly added It is an object of the present invention to provide a method for producing a sintered ore having improved productivity such as improving the method of blending solid combustibles, increasing the strength of the sintered ore, and improving the yield of the sintered ore.

[0016]

In order to achieve the above object, a method for producing a sintered ore according to the present invention comprises mixing an auxiliary material containing a solid combustible material with an iron oxide material as a main material. In producing a sinter by placing the sintering raw material in layers on a moving pallet by a chute, a solid combustible material is charged into the sintering raw material falling on the chute, The operation is performed by increasing the blended amount of the solid combustibles present in the upper layer portion of the sintering raw material packed layer placed on the upper side than the blended amount of the solid combustible materials in the packed layer present below the upper layer portion. The main point is to perform

In the present invention, charging a solid combustible material into the sintering raw material falling on the chute means that the sintering is performed by a drum mixer 22 or the like as shown in FIG. This means that the solid combustibles are mixed separately or in a separate system from the solid combustibles (such as coke breeze) which are preliminarily mixed with the raw material.

Further, in the present invention, the upper layer portion of the sintering material filling layer placed on the moving pallet is the sintering material filling layer portion including the embrittlement layer described in the prior art. However, although the embrittlement layer generated by sintering is present in the upper layer of the sintering material-filled layer, the width (depth) itself varies depending on the sintering conditions, so there is a part that cannot be specified unconditionally. . In the present invention, the portion where the amount of the solid combustible is increased is not necessarily required to be equal to or equal to the width (depth) of the embrittlement layer generated, and the effect of the present invention is exhibited. Then, it may be slightly larger or smaller than the width (depth) of the embrittlement layer generated. Furthermore, when mixing new solid combustibles with the sintering raw material that falls on the chute,
It is also technically difficult to mix the upper layer, which increases the amount of the solid combustible, so as to be equal to the width (depth) of the embrittlement layer. Therefore, in the present invention, the portion where the compounding amount of the solid combustible is increased is the upper layer portion of the sintering raw material filling layer in which the embrittlement layer easily occurs.

However, regarding the state of existence of the embrittlement layer in the upper part of the sintering material-filled layer, if the sintering conditions are operated in a substantially constant range, the embrittlement layer is generally at the highest level of the sintering material-filled layer. It occurs and exists at a depth of 30 to 50 mm from the surface. Therefore, based on the location of the embrittlement layer, the upper layer, which increases the amount of the solid combustible, is placed 30 mm from the outermost layer of the sintering material-filled layer in consideration of the case where the embrittlement layer becomes deeper.
Preferably, the depth is up to 100 mm.

In the present invention, the upper portion of the sintering material-packed layer placed on the moving pallet (particularly 30
In order to increase the compounding amount of solid combustible material (depth portion up to 100 mm) and to segregate the solid combustible material in the upper layer, the solid combustible material is burned while the sintering material falls on the chute. The biggest feature is that it is charged into the binding material. The term “the sintering raw material is falling on the chute” means not only the case where the solid combustible material is loaded on the chute, but also the case where the sintering raw material is falling on the chute bottom. Or a combination of the two.

The present inventors have found that the prior art such as the above-mentioned Japanese Patent Application Laid-Open No. 5-98358 cannot optimally control the blending or distribution of solid combustibles in a sintering raw material because it is newly added to the sintering raw material. It was found that the mixing time with the added solid combustibles could not be obtained. In this regard, while the sintering raw material falls on the chute and / or falls from the chute,
By charging a new solid combustible, the time required for the sintering raw material to accumulate on the moving pallet and the difference in the inertial force of the falling motion or different particle sizes of the sintering raw material and the solid combustible, In the lower part of the sintering raw material, uniform mixing of the sintering raw material and the solid combustible is achieved. This is because when falling on the chute and / or dropping from the chute, a kind of “sieving effect” occurs due to the difference in the movement of the drop and the inertial force, and the fine particles of the upper sintering raw material layer It is assumed that a phenomenon occurs in which coarse particles of the lower solid combustible material enter the particles of the upper sintering material layer at the same time as they enter the particles of the solid combustible material layer.

In order to exhibit this "sieving effect", it can be said that it is preferable to charge the sintering raw material with a solid combustible material as much as possible on the upstream side of the chute to increase the mixing time of both. However, this "sieving effect" varies depending on equipment conditions such as the angle and length of the chute, and operating conditions such as the supply amount and particle size of the sintering raw material, so that the optimum mixing position cannot be quantified in a straightforward manner. Therefore, the amount of the solid combustible present at a depth of 30 to 100 mm from the outermost layer of the sintering raw material packed layer placed on the moving pallet is preferably adjusted according to the application conditions. Even more preferably, 50% or more of the solid combustible material present in the depth portion is occupied by the solid combustible material having an average particle size of 0.5 to 3 mm so that the amount of the solid combustible material can be larger than that in the deeper portion. The distance (height) from the top of the chute or the lower end of the chute to the moving pallet so that the blending amount is 1.08 to 1.42 times the average blending amount of solid combustibles present in the deeper part.
Is selected or adjusted as appropriate.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Usually, a chute for depositing a sintering raw material on a moving pallet is a sloping (tilted) chute, which is made of steel or a chute provided with a belt, or a straight or curved chute. Is done. The direction of these chutes is usually arranged in the direction opposite to the direction of movement of the pallets so that the sintering materials are stacked on the moving pallets in descending order of grain size. Therefore, in the sintering machine having such a chute arrangement, the lower portion of the sintering material falling on the chute becomes the upper layer portion of the sintering material filling layer when deposited on the moving pallet. For this reason, when applying the present invention and trying to increase the concentration of solid combustibles in the upper part of the sintering raw material packed layer, a new solid material is formed below the sintering raw material packed layer that falls on the chute or falls from the chute. Preferably, a combustible is charged. Further, if the direction of the chute is arranged in the same direction as the moving direction of the pallet, a new solid flammable material is added to the upper layer of the sintering raw material packed layer falling on the chute, contrary to the above case. Load things. The same applies to the case where a solid combustible is charged into the sintering raw material falling from the lower end of the chute.

In the present invention, the larger the average particle size of the solid combustible material charged into the sintering raw material, the higher the strength of the sintered ore can be increased. preferable. The solid combustible material having an average particle size of 0.5 mm or more reduces 50% or more of the solid combustible material existing in the upper layer of the sintering raw material packed layer placed on the moving pallet to an average particle size of 0.5 to 0.5 mm. It is preferable to adjust the particle size distribution so as to occupy 3 mm. The reason why the particle size distribution of solid combustibles such as coke, breeze, and pulverized coal is preferable is that when the particle size of solid combustibles is less than 0.5 mm, the combustion of the solid combustibles into air rather than heat transfer to solid ores. This is because the heat transfer of the ore proceeds more preferentially, whereby the temperature of the ore does not sufficiently increase, a sufficient fusion bonding force between the ore particles cannot be obtained, and the strength may decrease. On the other hand, if the particle size of the solid combustibles exceeds 3 mm, the time until the solid combustibles are ignited by the ignition burner becomes longer, which may cause a reduction in production speed. By setting the solid combustible whose particle size distribution has been adjusted as described above to be 50% or more with respect to the blending amount in the upper layer portion, the above-described effects can be reliably exerted.

The amount of the solid combustibles present in the upper layer of the sintering raw material packed layer is determined from the viewpoint of improving the yield of the sinter.
For the blending amount in the lower part of the packed layer than in the upper part,
It is preferable to mix as much as possible. However, if the compounding amount is too large, on the contrary, the sintering speed starts to decrease, and the effect of improving the production rate decreases. It is preferable to adjust the average amount of combustibles to be 1.08 to 1.42 times. Therefore, the charging amount of the solid combustible to the sintering raw material falling on the chute is set to an amount corresponding to the charging amount.

In the case where a solid combustible is newly charged into the sintering material falling on the chute, there is no need to change the basic production conditions of the conventional sintered ore, and the basic production conditions are not affected. Is also not preferred. That is, in the present invention, it is preferable to change only the presence state of solid combustibles such as carbonaceous materials in the height direction of the sintering raw material packed bed. Therefore, the ordinary method for producing a sintered ore to which the present invention is not applied or the method for producing a sintered ore which has been carried out up to now is the same as the solid flammable ore mixed with the iron oxide raw material while keeping the heat input to the iron oxide raw material constant. It is preferable to keep the blending amount of the whole product constant. For this reason, in the present invention, the amount of the solid combustible material previously blended into the iron oxide raw material is an amount obtained by subtracting the charged amount of the new solid combustible material to be charged into the sintering raw material falling on the chute of the present invention, It is preferable that the compounding amount of the entire solid combustible compounded in the iron oxide raw material is substantially the same as that in the above-described production method to which the present invention is not applied.

As described above, the upper portion of the sintering material-packed layer for increasing the blending amount of the solid combustibles has a depth of 30 to 100 mm from the outermost layer of the sintering material-packed layer placed on the moving pallet. Is preferred. The depth of this upper layer is 30mm
If it is less than 3, the position is shifted from the location of the embrittlement layer, and as a result, the embrittlement layer still remains, and there is a possibility that the effect of the present invention cannot be obtained. Also, the depth of this upper layer is 100mm
Above, the amount of solid combustibles in the entire sintering material packed layer placed on the moving pallet only increases, and the solid combustibles are segregated into the embrittled layer in the upper part of the sintering material packed layer. This is because there is a possibility of deviating from the effect of eliminating only the embrittlement layer, which is the object of the present invention.

[0028]

1 and 2 schematically show an apparatus for charging a sintering raw material with a solid combustible material according to the present invention. In FIG. 1, reference numeral 4 denotes a hopper for a sintering raw material, which is a main raw material, and a sintering raw material 11 cut out quantitatively by a drum feeder 5 provided at a lower portion of the hopper 4 through a guide chute 10. 8 on top. Incidentally, the sintering raw material, which is the main raw material, is usually an iron oxide raw material and auxiliary raw materials, solid combustibles such as coke are previously mixed,
This is the same in the present invention. Reference numeral 6 denotes a hopper for a solid combustible to be newly added, which is provided upstream of the hopper 4 for the sintering raw material. The solid combustibles 15 to be newly added are:
From a supply port 7 provided in a lower part of the hopper 6, a sintering raw material 11 which is dropped (falls down) on the sloping chute 8 is supplied by a nozzle 9 provided on the sloping chute 8.

The method of charging the newly added solid combustible material into the lower portion of the sintering material falling on the chute is as follows.
It is preferable to employ a means for forcibly charging the lower part of the sintering raw material as described above. There is also a method of supplying the sintering raw material 11 by dropping it onto the solid combustible material 15 which naturally falls (falls) from the upstream side on the sloping chute 8, but the specific gravity and the amount of the solid combustible material and the sintering raw material are greatly different. In such a case, solid combustibles are scattered by the falling sintering raw material, and charging or mixing is not successful or dust is likely to be generated.
It is preferable to employ means for forcibly charging the lower part of the sintering raw material. The forced charging means is not limited to the nozzle 9, and other means such as a tunnel and a guide may be used as appropriate in addition to the nozzle 9.

The sintering raw material after charging a new solid combustible material has a basically two-layer structure of a solid combustible material layer at a lower portion and a sintering material layer at an upper portion. While being placed (stacked or deposited), when it falls on the sloping chute 8 and drops from the sloping chute 8, the lower solid combustible material layer and the upper sintering material layer are mixed, and the “sieving” is performed. By the effect, the lower layer becomes a sintering raw material layer having a high proportion of solid combustibles. The length of the sloping chute 9 for ensuring the mixing time between the lower solid combustible material layer and the upper sintering raw material layer is appropriately selected.
On the other hand, the moving pallet 1 is moving in the direction opposite to the direction in which the raw material flows down from the slopping chute 9. Then, the sintering raw material layer 2 in which the ratio of the lower portion of the iron oxide raw material and the like is high (the ratio of the solid combustibles is low) is placed in layers and sintered.

FIG. 2 shows another embodiment of the apparatus of FIG. 1, except that the solid combustible material is supplied from the hopper 12 through a drum feeder 13 and a guide chute 14 in a fixed amount. 1 has the same structure as the device of FIG. Reference numeral 9 denotes a nozzle as the forcible charging means as in FIG.

The method of supplying the solid combustible material onto the chute is, as shown in FIGS. 1 and 2, a method of free fall from a hopper or the like to the chute, or a method of mixing with air and blowing out from a nozzle (forced supply). ). However, as shown in FIGS. 1 and 2, when the fuel is supplied on a chute, the solid combustibles can be sufficiently mixed by a free-falling method. There is no. Also, in the case of mixing with air and blowing out from the nozzle, even if the sintering raw material is mixed while falling on the chute or falling from the chute, it blows through the sintering raw material layer,
Care should be taken not to adversely affect the state of filling of the sintering raw material on the moving pallet.

Example 1 Using the apparatus shown in FIG. 1, sintering raw materials were stacked, and sintered ore was produced in a cylindrical sintering pot having a diameter of 105 mm and a height of 370 mm. The conditions of the sintering raw material are low-cost iron ore such as high-crystal water ore as the iron oxide raw material, and 13.8% of limestone, 2.5% of quicklime, 1.8% of silica stone, and 5.
Using raw materials for actual sintering machines, which were added to 3% and turned into pseudo-particles,
The carbonaceous material (solid combustible) used was a sedimentation breathe with an average particle size of 0.5 mm. The charging conditions for the solid combustible material (charcoal material) were as follows: the amount of the sintering raw material charged was 360 kg / cycle, and the amount of the precipitating Breeze coke as the solid flammable material charged to the sintering raw material on the sloping chute. Was 0.72 kg / min, and the average blended amount was 5.5% (extrapolated). Sloping chute angle is 50 °, slide gate opening is 50mm, cutoff gauge height is 350mm, drum feeder rotation speed is 45
rpm, pallet truck moving speed was 2.0 m / min, and sintering material filling thickness was 300 mm. Furthermore, the sintering conditions are as follows: the sintering raw material charged on the pallet is charged into the cylindrical sintering pot,
Air was suctioned from the bottom of the pan with a fan, and the packed bed was ignited with a propane burner. At this time, the suction force of the fan was adjusted to be constant at 360 mmH ₂ O (3.53 kPa) until sintering was completed. The sintering was completed when the temperature immediately below the grate once increased and then returned to 200 ° C.

Under these conditions, a normal (conventional) charging method in which new solid combustibles are not added on the sloping chute, and new solid combustibles are added at a position 660 mm upstream from the lower end of the sloping chute. According to the charging method of the present invention, three types of the charging method of the present invention in which a new solid combustible is added at the lower end position of the sloping chute,
The sintering raw materials were stacked on a moving pallet, and the particle size and carbon distribution were measured by sampling 6 points at intervals of 20 mm from the surface of the packed bed to 100 mm in the depth direction at intervals of 20 mm, and at intervals of 50 mm below. . This packed bed was sintered in a sintering pot under the above conditions, and the drop strength and production rate of the sintered ore were measured.
The drop strength was evaluated by dropping the cake after sintering from a height of 2 m onto an iron plate four times and crushing the cake, and determining the weight ratio of those having a height of 5.0 mm or more.

In the method of the present invention in which the new solid combustible is added at a position 660 mm upstream from the lower end of the sloping chute, the distribution of carbon in the depth (height) direction of the packed bed is determined in the width direction of the packed bed. 3 is shown in FIG. As is apparent from FIG. 3, in the method of the present invention, there is a problem that the supplied solid combustible material can only be locally mixed, such as a streak in the width direction of the sintering raw material packed layer, as in the above-described conventional technique. There is no central part in the width direction of the sintering material packed bed (○
), East (△), west (◇),
The compounding amount of solid combustibles existing at a specific depth from the outermost layer of the sintering raw material packed layer can be increased uniformly in the width direction than the compounding amount of solid combustibles existing deeper than that. It is.

FIG. 4 shows the distribution of carbon in the depth (height) direction of the packed layer in each of the above methods. As is clear from FIG. 4, both the method of the present invention (△) and the method of the present invention (□) are 30 to 30 times smaller than the conventional method (○) from the outermost layer of the sintering raw material packed layer. The amount of solid combustibles present at a depth of up to 100 mm is 0.5 to 1.0% (1.08 to 1.
42 times). In addition, in the comparison between the methods of the present invention described above, a method of charging a new solid combustible when the sintering raw material falls on the chute and a method of charging a new solid combustible when the sintering material falls from the chute ( Method) and the 30
There is no difference in the amount of solid combustibles present at depths up to 100 mm. Therefore, when charging a new solid combustible material to the sintering raw material, the solid flammable material is charged when the sintering raw material is dropped on the chute or when dropped from the chute. It can be seen that there is an equivalent effect on the compounding of the product.

FIG. 5 shows the drop strength of each fired product (sinter). As is clear from FIG.
The sinter according to the method of the present invention, compared with the conventional method,
The drop strength is high and increases by 2.0 to 3.0%.

FIG. 6 shows the production rates of the above methods. The method of the present invention in which the compounding amount of the solid combustibles present in the depth portion from the outermost layer of the sintering raw material packed layer to 30 to 100 mm is larger than the average compounding amount of the solid combustibles present in the deeper portion, It can be seen that, as compared with the conventional method, the fired product (sinter) has a higher drop strength and a product yield is increased, thereby increasing the productivity.

Example 2 Under the same conditions as the method of the present invention of Example 1, except that only the average particle size of the solid combustible material to be blended was changed from 0.32 to 5.0 mm, the sintering raw material was stacked and sampled. Was performed to determine the particle size and the distribution of carbon. The packed bed was sintered in a sinter pot, and the drop strength of the sintered ore was measured. FIG. 7 shows the distribution of carbon in the depth (height) direction of the packed layer in each method. As is clear from FIG. 7, the method (marked with a triangle) where the average particle size of the solid combustible material is 0.5 to 1.0 mm, and 1.0 to 3.0 m
m method (marked with □) and the method in which the average particle size of solid combustibles is large
30 to 100 mm from the outermost layer of the sintering material packed layer
Up to 0.5% of the solid combustibles present in the deeper part than the solid combustibles present in the deeper part.
~ 1.0% (1.08 to 1.42 times) can be surely increased. However, even if the average particle size exceeds 3.0 mm, as in the method with an average particle size of 3.0 to 5.0 mm (marked by ◇), the average particle size is 0.32 mm.
From the standpoint of increasing the amount of solid combustibles and increasing the amount of solid combustibles as compared to the smaller method, the average particle size of the solid combustibles is preferably in the range of 0.5 to 3.0 mm. I understand.

FIG. 8 shows the drop strength of each fired product (sinter). As is clear from FIG.
The average particle size of the solid combustible is 0.5 to 1.0 mm or 1.0 to 3.
The larger the size is 0 mm (the average particle size is 0.5 mm or more), the higher the drop strength of the fired product can be compared to the method having the small average particle size of 0.32 mm. Therefore, the average particle diameter of the newly added solid combustible material is preferably 0.5 mm or more.

Example 3 Under the same conditions as in the method of Example 1 of the present invention, except that a solid combustible material (carbon material) to be newly added is used.
With only the addition (loading) amount of sintering varied from 0.22 to 1.39 kg, the sintering raw materials were stacked, and this packed bed was sintered in a sintering pot, and each position in the depth (height) direction of the packed bed was (100mm from the surface, 200m
m, 300 mm) and the retention time. Figure 9 shows the amount of added (charged) solid combustibles (charcoal) and
The relationship with the maximum temperature at each packed bed position is shown. As is clear from FIG. 9, when the amount of the solid combustible added to the sintering raw material increases, the maximum temperature at the position 100 mm from the surface layer (marked by ●) is the maximum temperature except when the amount of the solid combustible added is 1.39 kg. ,It is rising. Also, a slight rise in temperature is seen in the middle layer (marked by Δ) at a position 200 mm from the surface layer. The lower layer (◇) at a position 300 mm from the surface does not increase the amount of solid combustibles in this part even when solid combustibles are added. As it is, that is, the amount is the same as that of the prior art, the effect of increasing the temperature is naturally not seen.

FIG. 10 shows the addition of solid combustibles (charcoal).
(Charging) The amount and the holding time of the maximum temperature at each packed bed position are shown. Also, as in the case of the maximum attainable temperature, when the amount of the solid combustible added to the sintering material increases, the maximum attainable temperature holding time at a position 100 mm from the surface layer (marked by a solid circle) is the amount of the solid combustible added Is longer, except when it is 1.39kg. Also, the middle layer (200 mm from the surface)
(Mark), the retention time is slightly longer. This result is expressed as a heat retention index as shown in FIG. 11. When the amount of solid combustible (carbon material) added (charged) to the sintering material increases, the heat retention at a position 100 mm from the surface layer (marked by ●) It can be seen that the index has increased.

According to the third embodiment, the charging of the new solid combustible material on the chute in the method of the present invention is not limited to the improvement of the productivity due to the improvement of the yield of the sinter ore, but also the upper layer of the sintering raw material filling layer. It can be seen that there is an effect of improving the heat history from the part to the middle part or an effect of enabling control of the heat history. And improvement of this heat history or control of heat history
This is a very effective means in improving or controlling the production of the entire sintered ore.

[0044]

As described above, according to the method for producing a sintered ore according to the present invention, the sintering strength is increased, the amount of fine powder generated during crushing is reduced, and the yield of the sintered ore is improved. In addition to improving productivity, it also has the effect of improving the thermal history of the packed bed of sintering raw materials and the effect of enabling control of the thermal history, enabling the use of low-cost iron ore raw materials in large amounts and with high efficiency. The industrial significance is extremely large.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an outline of an apparatus (an experimental apparatus for a sintering machine) for charging a solid combustible material to a sintering raw material in the present invention.

FIG. 2 is a schematic explanatory view showing another embodiment of an apparatus (an experimental apparatus for a sintering machine) for charging a solid combustible material to a sintering raw material in the present invention.

FIG. 3 is an explanatory diagram showing a distribution of a carbon amount in a depth (height) direction of a sintering raw material packed layer in Example 1.

FIG. 4 is an explanatory diagram showing the distribution of the amount of carbon in the depth (height) direction of a sintering raw material packed layer in Example 1.

FIG. 5 is an explanatory diagram showing the drop strength of a fired product (sinter) in Example 1.

FIG. 6 is an explanatory diagram showing a production rate of a fired product (sinter) in Example 1.

FIG. 7 is an explanatory view showing the distribution of the amount of carbon in the depth (height) direction of a sintering raw material packed layer in Example 2.

FIG. 8 is an explanatory view showing the drop strength of a fired product (sinter) in Example 2.

FIG. 9 is an explanatory diagram showing the relationship between the amount of added (charged) solid combustibles (carbon materials) and the maximum temperature at the position of each packed bed of the sintering raw material in Example 3.

FIG. 10 is an explanatory diagram showing the relationship between the amount of addition (charging) of solid combustibles (carbon material) and the holding time of the maximum attainment temperature at each packed bed position of the sintering raw material in Example 3.

FIG. 11 is an explanatory diagram showing the relationship between the amount of added (charged) solid combustible material (carbon material) and the heat retention index at each packed bed position of the sintering raw material in Example 3.

FIG. 12 is a schematic explanatory view showing an outline of a typical Dwyroid (DL) type sintering machine as a sintering machine.

[Explanation of symbols]

Reference Signs List 1; moving pallet 2: lower sintering raw material filling layer 3: upper sintering raw material filling layer 4: sintering raw material hopper 5; drum feeder 6; solid combustible material hopper 7; opening 8; sloping chute 9; nozzle 10 Guide chute 11; sintering raw material 12; hopper 13 for solid combustibles; drum feeder 14; guide chute 15; solid combustibles.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshio Kimura 1 Kanazawacho, Kakogawa City, Hyogo Prefecture Kobe Steel Works Kakogawa Works

Claims (9)

[Claims] An iron oxide raw material as a main raw material is mixed in advance with an auxiliary raw material containing a solid combustible material to form a sintering raw material, and the sintering raw material is placed on a moving pallet by a chute and sintered. In the method for producing an ore, by charging a solid combustible material into the sintering raw material falling on the chute, the solid combustible material present in the upper layer portion of the sintering raw material packed layer placed on the moving pallet is removed. A method for producing a sintered ore, characterized in that the operation is carried out by increasing the blending amount to be greater than the blending amount of the solid combustibles present in the packed layer portion below the upper layer portion. 2. An upper layer portion of the sintering raw material filling layer is a portion having a depth of 30 to 100 mm from the outermost layer of the filling layer.
3. The method for producing a sintered ore according to item 1. 3. The method for producing a sintered ore according to claim 1, wherein the average particle diameter of the solid combustible material charged into the sintering raw material is 0.5 mm or more. 4. The sintered ore according to claim 1, wherein the solid combustible material present in the upper layer of the sintering raw material packed layer has an average particle size of 50% or more of 0.5 to 3 mm. Manufacturing method. 5. The amount of the solid combustibles present in the upper layer of the sintering raw material packed layer is 1.08 to 1.42 times the average compounded amount of the solid combustibles present in the lower part of the packed bed below the upper layer. The method for producing a sintered ore according to any one of claims 1 to 4, wherein 6. A solid combustible material is charged into a lower portion of a sintering raw material falling on the chute.
The method for producing a sintered ore according to the above item. 7. The method for producing a sintered ore according to claim 1, wherein the charging of the solid combustible is forcibly performed. 8. The method for producing a sintered ore according to claim 1, wherein the forcible charging of the solid combustible material is performed by a nozzle. 9. The amount of the solid combustible compounded in the iron oxide raw material is substantially the same as that in the case where the solid combustible material is not charged into the sintering raw material falling on the chute.
The method for producing a sintered ore according to any one of the above.