JPH07278684A - Sintered ore manufacturing method - Google Patents

Abstract

(57) [Abstract] [Purpose] A decrease in the yield of the product sintered ore that occurs when high-alumina ore containing 2.0% by weight or more of alumina component is used as a part of the blended raw material during the production of the sintered ore. Are prevented without degrading the quality. [Composition] Magnetite ore and / or scale containing 5.0 to 31.0 wt% of FeO component is added to the sintering raw material packed bed at the time of charging the raw material in a direction downward from the surface layer in the layer height direction.
It is added at a position of 0 mm or more and 200 mm or more in the surface layer direction from the bottom layer. As shown in FIG. 1, the addition amount is 0.5 to 10.0% by weight depending on the Al ₂ O ₃ content in the blended raw material. [Effect] It is possible to improve the deterioration of fluidity due to the increase of the alumina component, and to manufacture a high-quality sintered ore with a high yield.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sinter ore, ie, an iron ore sinter and a C, which is produced from a granular material by ventilation type self-combustion type sintering.
The present invention relates to a method for producing a sintered ore for alloys such as r, Mn, and Ti.

[0002]

2. Description of the Related Art A general sinter production process is shown in FIG.
Multiple brands of iron ore powder 1 cut out from the raw material tank are blended with limestone 4, powder coke 6, and in some cases silica stone, serpentine 5, etc., water is added with a drum mixer 7, and the mixed raw material is surged. Store in hopper 10. In the Dwightroid-type sintering machine 9, about 4 to 6 mm or more of sintered ore is placed on the moving pallet from the floor hopper 12 for about 10 to 50 m.
It is laid on the grate with a thickness of m and the sintering raw material is supplied from the surge hopper 10 by the charging device 11 to about 300-60.
After laying it with a thickness of 0 mm, the surface of the raw material layer is ignited in an ignition furnace and fired by downward suction, and crushed in the mine ore,
The particles are sized to obtain a product sinter. Normally -5 mm powder and normally +5 mm generated in the sieving process (not shown in Fig. 4)
The yield of the sintered ore is determined by the ratio of good lumps to the good lumps.

Sintered ore is widely used as a raw material to be charged into a blast furnace for producing pig iron, but in the Japanese steel industry, iron ore having various properties in order to obtain a sintered ore of stable quality. Generally, stone is blended and used as a sintering raw material. Among the iron ores blended in this way, high Al ₂ O containing 2.0% by weight or more of Al ₂ O _3.
3 Iron ore has various factors that adversely affect the sinterability, and as the Al ₂ O ₃ content in the sintering raw material increases, the yield of the ore, cold strength and low temperature reduction powdering index ( The quality of sinter such as RDI) tends to deteriorate.

Several countermeasures and raw material processing methods have been proposed for the factors causing deterioration in the case where a large amount of high Al ₂ O ₃ iron ore as described above is used as a sintering raw material.
For example, Japanese Patent Laid-Open No. 61-113729 discloses high Al.
A method is described in which ₂ O ₃ iron ore is mixed with a large amount of FeO component in a gradient. The purpose of this method is to suppress the formation of secondary hematite that occurs during the sintering reaction process and to improve the quality and yield of sinter by forming a sinter structure centered on calcium ferrite.

[0005]

Problems to be Solved by the Invention JP-A-61-1137
In the method described in Japanese Patent Publication No. 29, the fine mineral structure control by adding all layers of FeO components including the reduced iron powder is an improvement of a part of the sinter, so the sinter cake by densifying the powder ore and controlling the formation of through pores small effect not essential as compared to the overall improvement, baked ore quality (cold strength when Al ₂ O ₃ was used only low Al ₂ O ₃ ore of less than 2.0 wt%, the low temperature reduction powder Chemical conversion index) and yield are not reached.
Further, the addition of magnetite ore and scale to all layers greatly increases the production cost of sinter.

From the viewpoint of forming a sinter cake structure, Japanese Patent Application No. 5-139281 discloses a sintering raw material containing additives such as a substance containing metallic iron in order to enhance the melt fluidity of the middle and lower layers. Although the method of addition is described inside, in addition to the cost being high if the amount of additives is large, equipment costs such as the installation of new additive hoppers and the introduction of two-stage charging equipment for raw materials Has the drawback of increasing

The present invention reduces the yield of the product sintered ore in the method for producing the sintered ore in which a large amount of high Al ₂ O ₃ iron ore is blended, and reduces the cold strength and the low temperature reduction powdering index. The purpose is to prevent without degrading the quality.

[0008]

The method for producing a sinter according to the present invention is as follows.

[0009] Al ₂ O ₃ 5.0~70.0 when weight% using a high Al ₂ O ₃ ore containing 2.0% by weight or more as part of the mixed material during sintered ore production, FeO component Ore containing 5.0 to 31.0 wt% of
Alternatively, when the raw material is charged, the scale is placed at a position 200 mm or more downward from the surface layer in the layer height direction of the sintering raw material packed layer and 200 mm or more from the bottom layer to the surface layer direction in the raw material mixture.
A method for producing a sintered ore, which comprises adding an amount in a range shown by a slanted line in FIG. 1 according to the content of 1 ₂ O ₃ .

[0010] Al ₂ O ₃ 5.0~70.0 when weight% using a high Al ₂ O ₃ ore containing 2.0% by weight or more as part of the mixed material during sintered ore production, particle size Is 1-3
The magnetite ore and / or scale containing 5.0 to 31.0% by weight of FeO component of mm is 200 m downward from the surface layer in the layer height direction of the sintering raw material packed bed when the raw material is charged.
m or more and 200 mm or more in the surface layer direction from the lowermost layer, according to the Al ₂ O ₃ content in the blended raw material, an amount in the range shown by the slanted line in FIG. 1 is added. Production method.

[0011]

The present invention will be described in detail below.

[0012] Various causes have been considered as to the reason why the yield of the sintered ore decreases when the Al ₂ O ₃ content in the sintering compounded material increases. The fluidity of the melt generated during red hot melting has a great influence on the structure of the sinter cake formed after cooling, which in turn affects the quality of the product sinter such as yield, cold strength and low temperature reduction pulverization index. Found that If the melt fluidity is small, sufficient through pores will not develop,
A solid cake structure that does not allow solid coalescence will be formed, and the yield and strength will decrease. This is considered to be due to the formation of solid Al ₂ O ₃ -containing hardly soluble calcium ferrite.
That is, as shown in FIG. 5, when the Al ₂ O ₃ concentration exceeds 2%, the yield is sharply deteriorated because the fluidity of the melt generated in the sintering process is sharply reduced. That, Al ₂ O ₃ causes the component yield occurs when increased and sinter quality deterioration, Al ₂ to the secondary hematite
The influence of macroscopic structural changes such as the densification of fine ore particles is greater than the changes in the microscopic mineral composition such as the solid solution of O ₃ components and the increase in the production of calcium ferrite. This means that high Al ₂ O ₃ iron ore, namely Al ₂
In the case of ores containing O _{3 in an amount} of 2.0 wt% or more, it is important to improve the melt flowability, not the control of the mineral structure such as secondary hematite and calcium ferrite, in order to improve the yield and sinter quality. Is shown.

As a method for improving the melt fluidity, FeO,
CaO, fluoride, boron compound, barium compound 1
It is conceivable to add one kind or two or more kinds. However, the addition of CaO is limited under the operating conditions in the blast furnace, and its effect is also limited, so it is not possible to restore the optimum fluidity, and it is difficult to carry out, and a trace amount of effective fluoride is required. However, the addition of boron compounds, barium compounds, etc. has the drawback that the amount of iron charged to the blast furnace is relatively reduced by the amount of the additives. Therefore, it is effective to add a scale or magnetite ore that contains an FeO component that suppresses the formation of calcium ferrite and lowers the melting point by reducing the oxygen partial pressure, and is also effective as a heat source.

Further, as shown in FIG. 6, since the melt is not supplied from the upper portion to the upper layer portion of less than 200 mm from the surface layer of the sintering raw material packed layer, the excessive melt flow in the upper portion of the raw material layer remains in the solid portion. Becomes too thin, which rather adversely affects sintering. Therefore, it is important to improve the fluidity of the middle layer of the sintering raw material packed bed, which does not have proper ventilation holes and has poor air permeability, in order to improve the yield of the sintered ore. Furthermore, when iron scrap or granular pig iron is added only to the middle layer portion of 200 mm or more from the bottom layer to the surface layer, the additive components move not only to the middle layer but also to the lower layer portion due to the flow of the melt, and to the middle layer portion. By forming the appropriate ventilation holes, the through-pores in the lower layer portion are also affected by the formation, and the yield and air permeability are improved. Further, by charging the additive only to the middle layer portion, the amount of the additive added is reduced, so that the cost can be remarkably reduced. Therefore, the FeO component is 5.0 to 3
200 mm of magnetite ore and / or scale containing 1.0% by weight downward from the surface layer of the sintering raw material packed bed
Above, it was decided to insert at a position of 200 mm or more from the lowermost layer in the surface layer direction.

[0015] Therefore, as shown in FIG. 2, when using a high Al ₂ O ₃ ore 2 containing Al ₂ O ₃ 2.0 wt% or more as part of the mixed material during sintered ore production, FeO The magnetite ore containing 5.0 to 31.0 wt% of the component and / or the scale additive 8 is 200 mm or more downward from the surface layer in the layer height direction of the sintering raw material packed layer and 200 mm from the bottom layer toward the surface layer. The hopper 1 attached at the above position between the floor hopper 12 and the surge hopper 10.
0 ', blended raw material Al ₂ O As shown in FIG. 1 within the hatched
₍₃₎ Add 0.5 to 10.0% by weight of the whole blended raw material according to the content and fire. Since the melt fluidity deteriorates as the Al ₂ O ₃ content in the blended raw material increases, it is necessary to increase the amount of magnetite ore or scale added in order to recover it as the Al ₂ O ₃ component increases. However, if too much is added, the fluidity becomes excessive and the through pores become blocked, which has the opposite effect. Therefore, there is a proper range for the addition amount, and the range is as shown in FIG.

Further, as shown in FIG. 3, the grain size is 1 to 3 m.
The additive 8 of m is used in a particle size segregation type charging device 13 having a sieving function at the time of charging the raw material, and is 200 mm or more downward from the surface layer in the layer height direction of the sintering raw material packed layer and in the surface layer direction from the bottom layer. to 200mm or more positions, 0 in the entire mixed material in accordance with the content of Al ₂ O ₃ in the range shown in FIG. 1 within the hatched.
Add 5 to 10.0 wt% and bake. Here, the particle size segregation type charging device having a sieving function is, for example, as shown in Japanese Patent Publication No. 59-30776, Japanese Patent Publication No. 61-223136, and Japanese Patent Publication No. 3-31995.
This is a charging device in which parallel bars are provided at the tip of the run-up plate so that the vertical interval becomes wider toward the tip. When the raw materials are charged using these charging devices 13, particles having a particle size of 1 mm or more are charged in a portion of less than 200 mm from the surface layer to the lower layer, and most of particles having a particle size of more than 3 mm are directed from the lowermost layer to the surface layer. Since it is charged into a portion of less than 200 mm, the effect of densification of solid particles and formation of through pores due to improvement of fluidity cannot be effectively exhibited in the raw material packed bed. 1-3
The particles having a diameter of 2 mm are 200 mm or more below the surface layer in the layer height direction of the sintering raw material packed layer and 2 in the surface layer direction from the bottom layer.
It will be charged intensively in a proper layer of 00 mm or more.

By adding the additives as described above, it is possible to improve the deterioration of the fluidity due to the high Al ₂ O ₃ , and it is possible to produce a high-yield and high-quality sintered ore over the entire sintered layer. .

[0018]

Example 1 Using the sintering compounded raw materials shown in Table 1, the sintering operation was carried out by the conventional raw material charging method and the method shown in FIG. At this time, the height of the sintering raw material layer was 600 mm. The method of the present invention is 5.0% by weight of magnetite ore (Kudremuku ore) with respect to the blended raw material, and the method of the present invention is 1.0% by weight of magnetite ore (Kudremuku ore) and 3.0% by weight of the scale. In the method, 5.0% by weight of scale was similarly added from a hopper 10 'attached between the floor hopper 12 and the surge hopper 10 to a range of 200 mm or more and 400 mm or less below the surface layer in the height direction of the packed bed. All firing operating conditions were constant. As a result, as shown in FIG. 7, in the conventional method, the mixing ratio of high Al ₂ O ₃ iron ore (for example, A ore or B ore) was increased so that the average amount of Al ₂ O ₃ in the raw material was 1.21%. When it increased to 2.90%, the yield decreased by 7%, but in the method of the present invention, the yield improved by 3 to 10% as compared with the conventional method despite the increase in the average amount of Al ₂ O ₃ . Further, in the conventional method, the RDI was deteriorated by 3% due to the increase of the Al ₂ O ₃ component, but in the method of the present invention, the RDI was improved by 0 to 2% as compared with the conventional method.

[0019]

[Table 1]

[0020]

Example 2 Using the sintering compounded raw materials shown in Table 2, the raw material charging method was the conventional method and the sintering operation was carried out by the method shown in FIG. At this time, the height of the sintering raw material layer was 600 mm. In the method of the present invention, 3.0% by weight of magnetite ore (carol ore) having a particle diameter of 1 to 3 mm is added to the blended raw material, and in the method of the present invention, 4.0% by weight of a scale of 1 to 3 mm is also added to the tip of the runner plate. It was added in a range of 200 mm or more and 400 mm or less from the surface layer in the layer height direction of the packed bed by the charging device 13 provided with parallel bars whose vertical spacing increases as the distance increases.
As a result, as shown in FIG. 8, high Al ₂ O ₃ was obtained by the conventional method.
The yield decreased as the amount of ore compounded increased, and the coke consumption rate had to be increased to compensate for it. However, in the method of the present invention, the yield was increased despite the increase in the Al ₂ O ₃ component. When the increase in Al ₂ O ₃ component was small, the coke consumption rate could be reduced while maintaining the same yield. During the test operation, the cold strength and the sinter quality of the low temperature reduction powdering index hardly changed.

[0021]

[Table 2]

[0022]

EFFECTS OF THE INVENTION According to the present invention, the yield decreases due to the increase of the Al ₂ O ₃ component in the sintering raw material in the sinter production process, and the RD
It is possible to reduce the adverse effects such as the deterioration of I, and it is possible to improve the yield of the sintered ore manufacturing process and reduce the manufacturing cost.

[Brief description of drawings]

FIG. 1 is a diagram showing a range of an appropriate addition amount of scale and / or magnetite ore with respect to an Al ₂ O ₃ content.

FIG. 2 is a diagram showing steps of a method for producing a sintered ore according to the present invention.

FIG. 3 is a diagram showing steps of a method for producing a sinter according to the present invention.

FIG. 4 is a diagram showing steps of a conventional method for producing a sintered ore.

FIG. 5 is a diagram showing the effect of alumina concentration on the yield of a sintered ore in the prior art.

FIG. 6 is a diagram showing the influence of an additive addition position on a yield and a production rate in a sintering raw material packed bed having a layer height of 700 mm.

FIG. 7 is a diagram showing a relationship between an alumina concentration in a blended raw material and a yield in an example.

FIG. 8 is a diagram showing operation results in Examples.

[Explanation of symbols]

1 Iron ore powder 2 High Al ₂ O ₃ ore 3 Return ore 4 Limestone 5 Silica and serpentine 6 Powder coke 7 Drum mixer 8 Additive 9 Dwightroid type sintering machine 10 Surge hopper 10 'Hopper 11 Charging device 12 Floor hopper 13 Particle size segregation type charging device

Claims (2)

[Claims] 1. A Al ₂ O ₃ 5.0~70.0 when weight% using a high Al ₂ O ₃ ore containing 2.0% by weight or more as part of the mixed material during sintered ore production, Magnetite ore containing 5.0 to 31.0 wt% FeO component and /
Alternatively, when the raw material is charged, the scale is placed at a position 200 mm or more downward from the surface layer in the layer height direction of the sintering raw material packed layer and 200 mm or more from the bottom layer to the surface layer direction in the raw material mixture.
A method for producing a sintered ore, which comprises adding an amount in a range shown by a slanted line in FIG. 1 according to the content of 1 ₂ O ₃ . Wherein Al ₂ O ₃ 5.0-70.0 when weight% using a high Al ₂ O ₃ ore containing 2.0% by weight or more as part of the mixed material during sintered ore production, Particle size is 1-3m
The magnetite ore and / or scale containing 5.0 to 31.0% by weight of FeO component of m is 200 mm downward from the surface layer in the layer height direction of the sintering raw material filling layer when the raw material is charged.
Manufacturing of a sintered ore characterized by adding the above-mentioned amount and a distance of 200 mm or more from the lowermost layer to the surface layer in the range shown by the diagonal lines in FIG. 1 according to the Al ₂ O ₃ content in the compounded raw material. Method.