JP2000129324A - Apparatus for charging raw material for producing reduced iron - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charging apparatus that powdery iron ore and powdery solid reducing agent are used as raw materials and sheet-like formed material is formed by a roll compressing method and charged onto a rotary furnace hearth to obtain the high productivity of reduced iron. SOLUTION: This apparatus is provided with an upper roll 1, a lower roll 2, a film holder 15, a raw material supplying hopper 6, an inlet side guide 7 for upper and lower rolls and an outlet side guide 8 for upper and lower rolls set in the orthogonal direction to the shifting direction of the rotary furnace hearth. The apparatus may be provided with only the upper roll or the lower roll may be changed into plural parallel contacting rollers. For at least one of the upper roll and the lower roll, the rail-like continuous projections are provided near both edge parts in the width direction and a leveller is provided for the raw material supplying hopper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for horizontally mixing a raw material obtained by mixing a powdery iron raw material such as dust, sludge, scale or the like containing fine iron ore or iron and a powdery solid reducing agent such as coal or coke. The present invention relates to an apparatus for charging a raw material into a furnace when the reduced iron is manufactured by being charged into a heating hearth that rotates and moves.

[0002]

2. Description of the Related Art In recent years, a heating hearth (hereinafter referred to as a "rotating hearth") in which a powdery iron ore and a powdery solid reducing agent are mixed and agglomerated, and the resulting agglomerate is horizontally rotated. The technology of producing reduced iron by charging it into a furnace has attracted attention.

[0003] Unlike a rotary kiln furnace which has been used for a long time, the rotary hearth has a low equipment cost. However, since the hearth rotates horizontally, care must be taken in charging raw materials and discharging products. A typical example of the technology is disclosed in
JP-A-238307 discloses a technique in which powdery iron ore and a solid reducing agent are mixed to form pellets, and the pellets are heated to a high temperature to reduce iron oxide in the iron ore to obtain solid metallic iron.

FIG. 5 is a schematic view showing an example of a conventional process for producing reduced iron using a rotary hearth. As shown in the figure, bentonite, moisture and tar are added as binders to fine iron ore and fine coal and mixed with a kneader.
This mixed raw material is agglomerated (pelletized or briquetted) by a pelletizer or a double roll compressor, transferred to the raw material charging section at the upper part of the rotary hearth furnace, and charged into the rotary hearth furnace.
The iron oxide in the iron ore is reduced to solid metallic iron during one rotation of the hearth, and the obtained metallic iron is taken out from the discharge part.

[0005] Heating of the rotary hearth furnace is mainly performed from the surface of the raw material layer by radiation to the raw material layer, and the amount of heat received per unit area of the hearth is the same. It is important not to make it from the aspect of improving thermal efficiency.
Therefore, it is important in terms of productivity of reduced iron to increase the bulk density (t / m ³ ) (hereinafter, also referred to as the charging density) when charged into the rotary bed furnace.

[0006] The pellets or briquettes are agglomerated by a pelletizer or a double-roll compressor, and therefore have a relatively high density in a simple substance. There is a problem that the production rate (t / D · m ² ) per area and per day does not increase.

[0007] In the rotary hearth, fuel gas and air are fed into the furnace, and the fuel gas is burned.
A furnace temperature of 1300 ° C. is ensured. Pellets or briquettes are 10 to 20 m on the hearth of this rotary hearth furnace.
m, and radiated heat mainly from the inner wall of the furnace.
When heated to 0 ° C. or higher, reduced and sintered, and reaches a predetermined metallization ratio, it is discharged as a product outside the furnace.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a charging apparatus having a high charging density and a high reduced iron production rate (t / D · m ² ) which can be charged on a rotary hearth. Is to do.

[0009]

Means for Solving the Problems The present inventors have studied to solve the above-mentioned problems, and as a result, have obtained the following findings (A) to (D).

(A) Since the sheet-shaped raw material compression molding is poor in elasticity, cracks are easily generated by bending stress when it is passed through a charging device having a curvature, and the sheet-shaped raw material compression molded product is put on a rotary hearth. When charging, a charging device having a fixed angle with respect to the rotary hearth is required.

(B) The structure of the apparatus for compressing and forming via a film may be any of an upper roll, an upper roll and a plurality of parallel rollers, or only an upper roll.

(C) If at least one of the upper and lower rolls is provided with continuous rail-shaped protrusions near both ends in the roll width direction, the density (t / m ³ ) of the formed product in the width direction can be made uniform. And the production rate of reduced iron (t / D · m ² ) can be increased.

(D) If a leveler is installed in the raw material supply hopper located on the upstream side of the compression molding apparatus and the cutout amount is adjusted, the density in the width direction of the molded product can be made uniform, and the reduced iron production rate (t / D · m ² ) can be increased.

The present invention has been made based on the above findings, and the gist is as follows (1) to (6).

(1) A mixed raw material of powdered iron raw material and powdered solid reducing agent is compressed and formed by a roll above a rotary hearth moving horizontally and a sheet-like molded product is obtained on the rotary hearth. It is a device that is charged and fired to produce reduced iron, and an upper roll installed in a direction perpendicular to the moving direction of the rotary hearth, and a lower roll disposed below the upper roll,
A film holder that passes through the upper part of the lower roll and supplies a film for loading a sheet-like molded product; a raw material supply hopper upstream of the upper roll; An upper and lower roll entrance guide arranged between the sides so as to be in contact with the back side of the film, and disposed between the exit side of the upper and lower rolls and the rotary hearth so as to be in contact with the back side of the film. An apparatus for charging a raw material for producing reduced iron, comprising an upper and lower roll exit side guide.

(2) A mixed raw material of powdered iron raw material and powdered solid reducing agent is compressed and formed by a roll above a rotary hearth moving horizontally and a sheet-like molded product obtained is placed on the rotary hearth. An apparatus for producing reduced iron by charging and firing an upper roll installed in a direction orthogonal to the direction of movement of the rotary hearth, and passed through the lower part of the upper roll to form a sheet-like molded product A film holder for supplying a film for loading, a raw material supply hopper upstream of the upper roll, and a lower side portion of the film disposed between the raw material supply hopper and the rotary hearth so as to be in contact with the back side of the film. An apparatus for charging a raw material for producing reduced iron, comprising:

(3) A mixed raw material of powdered iron raw material and powdered solid reducing agent is compressed and formed by a roll above a rotary hearth moving horizontally and a sheet-like molded product is obtained on the rotary hearth. An apparatus for producing reduced iron by charging and firing, comprising: an upper roll installed in a direction orthogonal to a moving direction of a rotary hearth; and a plurality of juxtaposed rollers arranged below the upper roll. And a film holder that is passed over the plurality of juxtaposed rollers and supplies a film for loading a sheet-like molded product, a raw material supply hopper upstream of the upper roll, and the raw material supply hopper. An upper roll entrance guide disposed so as to be in contact with the back side of the film between the entrance sides of the upper roll, and a back side of the film between an exit side of the plurality of juxtaposed rollers and the rotary hearth. Upper roll placed in contact with the part The charging device producing reduced iron raw material and having a side guide.

(4) In the apparatus according to the above (1),
An apparatus for charging a reduced iron production raw material, wherein at least one of an upper roll and a lower roll has continuous rail-shaped projections in the circumferential direction near both ends in the roll width direction.

(5) The apparatus according to the above (2) or (3), wherein the upper roll has continuous rail-shaped protrusions in the circumferential direction near both ends in the roll width direction. Equipment for charging iron production raw materials.

(6) The apparatus according to any one of (1) to (5) above, wherein the raw material supply hopper has a leveler.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a longitudinal sectional view conceptually showing an apparatus according to claims 1 to 3, and FIG. 1 (a) shows an apparatus based on claim 1. 1 (b) is claim 2
FIG. 1 (c) is a longitudinal sectional view showing an apparatus based on the third embodiment, respectively.

(1) As shown in FIG.
Is a rotary hearth 1 that moves horizontally.
6, a mixed raw material 4 of a powdered iron raw material and a powdered solid reducing agent
Is compressed and molded with a roll to obtain a sheet-like molded product 5
Is mounted on the rotary hearth 16 and fired to produce reduced iron, comprising: an upper roll 1 installed in a direction orthogonal to the moving direction of the rotary hearth 16; , A film holder 15 passed through the upper part of the lower roll and supplying a film 3 for loading a sheet-like molded product, and a raw material supply hopper upstream of the upper roll 1 An upper / lower roll inlet guide 7 disposed between the raw material supply hopper 6 and the inlet side of the upper roll 1 so as to be in contact with the back side of the film; an outlet side of the upper and lower rolls; And an upper and lower roll exit guide 8 disposed so as to be in contact with the back side of the film 3 between the mold 3 and the molded product 5. And the corner formed by the upper and lower roll exit side guides 8 ) It can be stably placed on the rotary hearth in. .

The upper and lower roll exit side guides 8 and the upper and lower roll entrance side guides 7 may be plate-shaped ones as long as they can secure a certain angle.

"Powdered iron raw material" is a powdered iron raw material containing iron oxide as a main component. Specifically, the above-mentioned powdered iron ore or dust containing iron generated at an ironworks, It refers to sludge (eg, sintering machine generated dust, blast furnace generated dust, converter generated dust, rolling plant generated sludge), scale, and the like. In the present invention, these can be used alone or in a mixture of two or more.

The "pulverized solid reducing agent" is a powder of a solid substance mainly containing carbon such as coal, coke, char and oil coke. These can also be used alone or in combination of two or more.

(2) As shown in FIG.
Is a rotary hearth 1 that moves horizontally.
6, a mixed raw material 4 of a powdered iron raw material and a powdered solid reducing agent
Is compressed and molded with a roll to obtain a sheet-like molded product 5
Is mounted on the rotary hearth 16 and baked to produce reduced iron, comprising an upper roll 1 installed in a direction orthogonal to the direction of movement of the rotary hearth 16, and a lower part of the upper roll. A film holder 15 for supplying a film 3 for loading a sheet-shaped molded product, a raw material supply hopper 6 on the upstream side of the upper roll, the raw material supply hopper 6, the rotary hearth 16, And a guide 10 disposed so as to be in contact with the back side of the film. The molded object 5 is formed at a fixed inclination angle (formed by the rotary hearth 16 and the guide 10) in the rotational movement direction of the rotary hearth. At an angle), and can be stably mounted on the rotary hearth. The guide 10 may be a plate-shaped one that can secure a constant inclination angle.

(3) As shown in FIG.
Is a rotary hearth 1 that moves horizontally.
6, a mixed raw material 4 of a powdered iron raw material and a powdered solid reducing agent
Is compressed and molded with a roll to obtain a sheet-like molded product 5
Is mounted on the rotary hearth 16 and calcined to produce reduced iron, comprising: an upper roll 1 installed in a direction orthogonal to a moving direction of the rotary hearth 16; A plurality of juxtaposed rollers 12 arranged at a lower portion, a film holder 15 which is passed through the upper portions of the plurality of juxtaposed rollers 12 and supplies a film 3 for loading a sheet-like molded product, and the upper roll 1 A material supply hopper 6 on the upstream side of the upper roll, an upper roll entry side guide 11 disposed between the material supply hopper 6 and the entry side of the upper roll 1 so as to be in contact with the back side of the film, An upper roll exit guide 13 disposed between the exit side of the juxtaposition roller 12 and the rotary hearth 16 so as to be in contact with the back side of the film 3; Angle of rotation (rotary hearth 16 On the roll exit side guide 13 guide 1
(The angle formed by 0) on the rotary hearth.

A plurality of juxtaposed rollers 12
Any material that can withstand a load when a load is applied to a sheet-like molded product by using the above method may be used. The upper roll exit side guide 13 and the upper roll entrance side guide 11 may be plate-shaped ones as long as they can secure a constant inclination angle.

(4) FIG. 2 is a view conceptually showing the protrusion according to claim 4, and FIG. 2 (a) shows a rail-like shape in the circumferential direction near both ends of the upper roll 1 in the roll width direction. The longitudinal cross-sectional view when the continuous protrusions 14 are installed is shown, in which A type is installed at the roll edge, B type is installed near the edge, and FIG. Continuous protrusions 14 in the circumferential direction near both ends of the
FIG. 4C shows a case where rail-shaped continuous protrusions 14 are provided in the circumferential direction near both ends of the upper roll 1 and the lower roll 2 in the roll width direction.

As shown in FIGS. 3A to 3C, by providing the projections 14 on at least one of the upper roll 1 and the lower roll 2, the density of the molded product 5 in the width direction can be made uniform. .

(5) FIG. 3 is a view conceptually showing the protrusion according to the fifth aspect. As shown in the figure, the rail-shaped continuous protrusions 14 are provided in the circumferential direction near both ends of the upper roll in the roll width direction, so that the density of the molded product 5 in the width direction can be made uniform.

(6) The shape of the projection shown in FIGS.
Although the cross section is rectangular, the cross section may be R-shaped or trapezoidal as long as the raw material can be pressed in the width direction.

(7) The leveler 17 of the raw material supply hopper 6 installed on the upper roll side of the raw material hopper according to claim 6.
Is installed on the upper roll side of the raw material hopper 6 as shown in FIG. 4, but it is sufficient if the cutout thickness of the raw material can be made uniform by a vertical slide structure.

The film to be used must be wide, long, and thin, and must burn in a rotary hearth. Those containing inorganic components are also slightly contained in reduced iron products,
A hydrocarbon-based or carbohydrate-based one containing almost no inorganic component is desirable. The use of polyethylene and paper as film materials facilitates the aforementioned conditions of being wide, long and thin, and not burning in a rotary hearth to introduce impurities into reduced products. Can be satisfied. It also has the advantage of low cost.

By setting the inclination angle to 5 to 60 degrees, slip of the molded product can be prevented. The reason for setting the inclination angle to 5 to 60 degrees is that if it is less than 5 degrees, the equipment length is unnecessarily long and it is not economical, and if it exceeds 60 degrees, the molded article may slip and impair the shape of the sheet. Preferably, 15
~ 30 degrees.

In the case of a wide molded product to be supplied to a wide rotary hearth, a plurality of devices are arranged in a direction orthogonal to the direction in which the horizontally rotating rotary hearth moves, so that a wide width is obtained. What is necessary is just to make the density of the molded product uniform in the width direction on the rotary hearth. The wide rotating hearth means a hearth width of 4 m or more. Since a normal roll width is about 1 m, four or more lines are required. However, if the arrangement is the same, the roll driving portion interferes. It is preferable to arrange a plurality of units in a staggered pattern.

The peripheral speed of each roll is synchronized with the peripheral speed of the rotary hearth rotating horizontally. By this synchronizing operation, a tensile or compressive stress or the like is not applied to the sheet-like molded product, so that the shape of the molded product can be kept good.

[0038]

EXAMPLES Fine iron ore shown in Table 1 and fine coal shown in Table 2 were blended at a blending ratio shown in Table 3. Using this mixed raw material, reduced iron as a sheet-like molded product (thickness: about 15 mm, constant width about 1 m) was manufactured under the conditions shown in Table 5, and the production rates were compared to compare the effects of the present invention. evaluated. In addition,
Table 4 shows the equipment specifications and operating conditions of the rotary hearth used.

In the example of the present invention, the peripheral speed of each roll of the apparatus of the present invention shown in FIG. 1 and the peripheral speed of the rotary hearth rotating horizontally were synchronized, and the test of the present invention example was performed under a constant condition of an inclination angle of 20 °. The film used is 0.1 mm thick polyethylene or 30 g / m ² paper.

In the conventional example, a beret is produced by a pelletizer shown in FIG. 5, and a briquette is produced by a double roll compressor.
o. In case No. 1, a pellet having a diameter of 20 mm was manufactured using a dish-type pelletizer having a diameter of 7.5 m, and the pellet was charged into a rotary bed furnace with a flat plate chute. The case of No. 2 is No. In this case, briquettes are used in place of the pellets in case 1.

In Example No. of the present invention, The cases of Nos. 3 to 8 are Nos. When there is no leveler. 9 to 14 are cases where there is a leveler.

No. Cases 15 to 30 are cases in which projections are installed on the rolls shown in FIGS. 2 and 3 in addition to the leveler.

As shown in Table 5, the production rate of the example of the present invention can be higher than that of the conventional example, and the charging density of the sheet-like molded product into the rotary hearth can be reduced by attaching a leveler to the raw material hopper. It was possible to increase the production rate.

Further, by adding protrusions to the roll, the charging density and the production rate could be further increased.

The pellet and briquette moldings of the comparative example had a high density of a single substance of 2.4, but the charging density to the rotary hearth was lower than that of the sheet-like molding, and the production rate was 2%.
The value was as low as t / D · m ² or less.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

[Table 3]

[0049]

[Table 4]

[0050]

[Table 5]

[0051]

According to the present invention, a sheet-like molded product can be produced by a roll compression method using powdery iron ore and a powdery solid reducing agent as raw materials, and cracks are formed on the surface of the molded product. It is possible to charge on a rotary hearth without occurring,
The production rate of reduced iron can be increased.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view conceptually showing the contents of an apparatus according to claims 1 to 3, wherein FIG. 1 (a) shows an apparatus based on claim 1, and FIG. FIG. 1C is a longitudinal sectional view showing an apparatus according to claim 2, and FIG. 1C is a longitudinal sectional view showing an apparatus according to claim 3.

FIGS. 2A and 2B are diagrams conceptually showing the protrusion according to claim 4, wherein FIG. 2A shows a rail-shaped protrusion on an upper roll, and FIG. FIG. 3C is a diagram showing a case where rail-shaped protrusions are installed on the upper roll and the lower roll.

FIG. 3 is a view conceptually showing the projection according to claim 5, and is a view showing a case where a rail-shaped projection is installed on an upper roll.

FIG. 4 is a view conceptually showing the leveler according to claim 6, which has a structure that slides up and down.

FIG. 5 is a schematic view of an example of a conventional reduced iron production process performed using a rotary hearth.

[Explanation of symbols]

 1: Upper roll 2: Lower roll 3: Film 4: Mixed raw material 5: Molded material 6: Raw material supply hopper 7: Upper and lower roll entrance side guide 8: Upper and lower roll exit side guide 10: Guide 11: Upper roll entrance side guide 12: Plural parallel rollers 13: Upper roll exit side guide 14: Projection 15: Film holder 16: Rotating hearth 17: Leveler

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuo Kamei 4-5-33 Kitahama, Chuo-ku, Osaka City Inside Sumitomo Metal Industries, Ltd. (72) Inventor Yoshihisa Nakamura 4-5-33 Kitahama, Chuo-ku, Osaka City Sumitomo Metal Industries Co., Ltd. F-term (reference) 4K001 AA10 BA02 BA14 BA15 CA01 CA16 GA19 GB01 HA01 4K012 DE01 DE03 4K050 AA04 BA02 CA09 DA03

Claims (6)

[Claims] 1. A mixed raw material of a powdered iron raw material and a powdered solid reducing agent is compressed and rolled above a rotary hearth moving horizontally.
Forming, charging the obtained sheet-shaped molded product on the rotary hearth, and firing to produce reduced iron, an upper roll installed in a direction perpendicular to the moving direction of the rotary hearth, A lower roll disposed below the upper roll, a film holder passed through the upper portion of the lower roll and supplying a film for loading a sheet-like molded product, and a raw material upstream of the upper roll A supply hopper, an upper / lower roll inlet guide disposed so as to be in contact with the back side of the film between the raw material supply hopper and the upper roll input side, and a space between the upper and lower roll output sides and the rotary hearth. And an upper / lower roll exit guide disposed so as to be in contact with the back side of the film. 2. A mixed raw material of powdered iron raw material and powdered solid reducing agent is compressed and rolled by a roll above a rotary hearth moving horizontally.
Forming, charging the obtained sheet-shaped molded product on the rotary hearth, and firing to produce reduced iron, an upper roll installed in a direction perpendicular to the moving direction of the rotary hearth, A film holder that is passed through the lower part of the upper roll and supplies a film for loading a sheet-like molded product;
A reduced iron comprising: a raw material supply hopper upstream of the upper roll; and a guide disposed between the raw material supply hopper and the rotary hearth so as to be in contact with the back side of the film. Equipment for charging production raw materials. 3. A raw material mixture of a powdered iron raw material and a powdered solid reducing agent is compressed and rolled above a rotary hearth moving horizontally.
Forming, charging the obtained sheet-shaped molded product on the rotary hearth, and firing to produce reduced iron, an upper roll installed in a direction perpendicular to the moving direction of the rotary hearth, A plurality of juxtaposition rollers arranged at a lower part of the upper roll, a film holder passed through an upper part of the plurality of juxtaposition rollers, and supplying a film for loading a sheet-like molded product, and the upper roll A raw material supply hopper on the upstream side, an upper roll inlet side guide disposed between the input side of the raw material supply hopper and the upper roll so as to be in contact with the back side of the film, and the plurality of parallel rollers. An apparatus for charging a raw material for producing reduced iron, comprising: an upper roll exit side guide disposed between an exit side and the rotary hearth so as to be in contact with a back side of the film. 4. The apparatus according to claim 1, wherein at least one of the upper roll and the lower roll has a continuous rail-shaped protrusion in the circumferential direction near both ends in the roll width direction. Equipment for loading reduced iron production raw materials. 5. The reduced iron production raw material according to claim 2, wherein the apparatus has a continuous rail-shaped projection in the circumferential direction near both ends in the roll width direction of the upper roll. Charging device. 6. An apparatus according to any one of claims 1 to 5, wherein the raw material supply hopper has a leveler.