WO2003029740A1

WO2003029740A1 - Raw material loading device for rotary hearth furnace

Info

Publication number: WO2003029740A1
Application number: PCT/JP2002/009470
Authority: WO
Inventors: Hiroshi Ichikawa
Original assignee: Nippon Steel Corporation
Priority date: 2001-09-28
Filing date: 2002-09-13
Publication date: 2003-04-10
Also published as: JP2003106775A; TW567300B

Abstract

In order to solve the problem of raw material blocking or getting caught even in the case of small-scale processing, to make it easier for raw material to form a single layer on the hearth, to ensure uniform feeding widthwise of the furnace, to minimize differences in temperature among raw material positions, to make the reduction rate substantially constant, and to improve productivity, one end of a loading device is fixed to a frame body, while the other end is formed with an open end defined by connecting a plurality of continuous straight lines or curves, the plurality of continuous straight lines or curves being straight lines or curves that successively connect the intersections between imaginary lines widthwise dividing the hearth surface and straight lines parallel with the direction of movement of raw material in the loading device, and satisfying particular conditions. Preferably a leveling tool for leveling the raw material in uniform thickness is installed between the frame body of the loading device and the open end of the bottom plate. Further, preferably the loading device is inclined at an angle that is not less than the angle of repose of the raw material or is disposed at an angle that is less than the angle of repose, and a raw material moving device is installed.

Description

Description Raw material charging equipment for rotary hearth furnaces Technical field

The present invention relates to a method for heating and reducing iron oxide agglomerates including scale, sludge, dust and the like generated in a steel mill, etc., to produce reduced iron agglomerates in a rotary hearth furnace. It relates to a device for charging iron agglomerates. Background art

There are many proposals for a device for charging a raw material into a rotary hearth furnace. One of them is using a vibrating conveyor. An opening is provided at the end of the vibrating conveyor over the furnace width of the rotary hearth furnace, and the raw material conveyed on the conveyor is dropped from the opening to the hearth surface by vibration and charged. Vibration can drop a uniform amount in the furnace width direction, but if the hearth area per unit furnace width differs between the inner and outer circumferences as in a rotary hearth furnace, When the volume is dropped, the volume becomes smaller on the outer circumference of the hearth than on the inner circumference. If it is inserted along the outer circumference, the inner volume will be excessive.

U.S. Pat. No. 5,589,215 discloses a raw material charging table mounted on a rotary hearth furnace. This table extends across the rotary hearth and has a first end provided with a distribution member and a second end provided with a plurality of discharge slots. From the discharge slot, into a curtain, and charged over the entire width of the rotary hearth that passes under the table.

In the middle between the first and second ends of the table, the raw material should be of uniform thickness (one layer). Is equipped with a leveling tool for adjusting to. In addition, one discharge slot is provided in each of several grooves separated by a longitudinal partition (partition), and the inclination angle of the slot can be changed between the inner diameter side and the outer diameter side of the hearth. The amount of raw material charged in the width direction of the hearth is adjusted to ensure that the raw material is evenly distributed over the entire hearth.

Japanese Patent Application Laid-Open No. 11-293317 discloses that a frontage of a passage partitioned by a partition as described above is supplied from a frontage of a passage for guiding a raw material to be introduced into an outer peripheral portion of a rotary hearth to a raw material introduced into an inner peripheral portion. There is disclosed a charging device that is gradually narrowed to a frontage of a passage for guiding a vehicle.

Japanese Patent Application Laid-Open No. 2000-310488 also discloses a charging method in which the lower side of the leveling tool is inclined to adjust the gap with the table surface so that the supply amount of the raw material is different in the width direction. An apparatus is disclosed.

In the technology of the above-mentioned USP5895215, since a plurality of discharge slots are provided, a partition for partitioning each discharge slot is indispensable.When the processing scale is reduced, the intervals between the partitions are narrowed accordingly, and the charged raw material is reduced. As the size of the (molded product) approaches, there is a problem that clogging and catching may occur.

In the technique disclosed in Japanese Patent Application Laid-Open No. 11-293317, the frontage of the passage for guiding the raw material to be introduced into the outer peripheral portion is gradually narrowed as it advances, so that clogging and catching are likely to occur. Further, in the technology disclosed in Japanese Patent Application Laid-Open No. 2000-310488, since the supply amount is adjusted by the number of layers of the raw material (molded body) on the table, it is difficult to form a single layer even on the hearth. For this reason, the heat transfer of the raw material to the lower part of the layer is delayed, and the reduction rate at the lower part of the layer is reduced, and the productivity is reduced.

As described above, in the case where the partition plate is installed, the raw material is clogged in the partition, and the raw material cannot be charged into the rotary hearth surface. In the case of adjusting the amount of charging in the width direction of the rotary hearth furnace by inclining the lower side of the leveling tool in the width direction, it is charged into the rotary hearth furnace. Uniform charging cannot be achieved only by changing the material layer. Disclosure of the invention

Therefore, the problem to be solved by the present invention is to solve the problem of clogging and catching of raw materials even when the processing scale is small when charging raw materials into a rotary hearth furnace, and to reduce the raw material on the hearth to one layer. In other words, it is necessary to improve the productivity by making it easy to supply the raw material uniformly in the furnace width direction, reducing the temperature difference depending on the raw material position, keeping the reduction rate almost constant.

The present invention for solving the above-mentioned problems is directed to a raw material charging apparatus for a rotary hearth furnace for charging and heating and reducing a raw material on a hearth surface, wherein one end of a bottom plate of the charging apparatus is the charging apparatus. The other end has an open end formed by connecting a plurality of continuous straight lines or curved lines, and the plurality of continuous straight lines or curved lines include a virtual line obtained by dividing the hearth surface in the width direction; A raw material charging apparatus for a rotary hearth furnace, wherein the raw material charging apparatus is a straight line or a curved line connecting intersections of a straight line parallel to a raw material moving direction of the charging apparatus, and satisfying the expression (1). It is.

A / a = B / b = C / c = D / d ... (1) A, B, C, D: Surface area when the hearth surface is divided in the width direction a, b, c, d ... The other bottom plate Projection length of each straight line or curve at the end in the direction perpendicular to the direction of material movement

In the present invention, between the frame and the bottom plate opening end of the charging device.

It is preferable to provide a leveling device for leveling the raw material to a uniform thickness.

In addition, it is preferable that the charging device is inclined at an angle equal to or larger than the angle of repose of the raw material, or the charging device is disposed at a angle of less than the angle of repose of the raw material, and a raw material moving device is provided. BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a plan view of a hearth and a charging device of a rotary hearth furnace showing an example of the present invention.

FIG. 2 is a perspective view showing an example of the charging device according to the present invention.

FIG. 3 shows an example of the charging device according to the present invention, and is a cross-sectional view taken along the line AA of FIG. BEST MODE FOR CARRYING OUT THE INVENTION

The apparatus of the present invention will be described with reference to the examples of FIGS. FIG. 1 is a plan view of a rotary hearth furnace in which a charging device 1 is provided on a hearth. FIG. 2 is a perspective view of the charging device 1. FIG. 3 is a sectional view of the charging device 1.

One end of the bottom plate 2 of the charging device 1 is fixed to the frame 12 of the device 1, and the other end is formed of a plurality of (four in this example) continuous straight lines 3, 4, 5, 6 as shown in FIG. An open end is formed in a tied shape. A plurality of continuous straight lines 3, 4, 5, and 6, as shown in the example of FIG. And a condition that satisfies the above equation (1).

In FIG. 1, reference numeral 7 denotes a furnace outer wall, 8 denotes a furnace inner wall, and a space between the furnace walls. In this example, the hearth surface is divided into four in the width direction, and the surface areas are A, B, C, and D from the outer peripheral side. The lengths (projected lengths) when projecting the continuous straight lines 3 to 6 forming the opening end of the bottom plate 2 in a direction perpendicular to the moving direction of the raw materials were defined as a, b, c, and d from the outer peripheral side. Multiple continuous straight lines may be continuous curves.

By forming the open end of the bottom plate 2 in this manner, the raw material can be uniformly supplied from the inner peripheral side to the outer peripheral side of the hearth without partitioning the bottom plate 2 by a partition or the like.

In the apparatus of the present invention, the frame 12 of the charging device 1 and the continuous straight lines 3 to 6 By disposing the leveling tool 9 for leveling the raw material 11 to a uniform thickness between the open end portions of the bottom plate as shown, the raw material can be more uniformly supplied to the hearth.

When the charging device 1 is tilted to the angle of repose of the raw material 11 or more, the raw material 11 on the bottom plate 2 moves toward the opening end by its own weight and is supplied to the hearth without vibrating the device. When the inclination is set to less than the angle of repose, the raw material 11 moves toward the opening end and is supplied to the hearth by providing a raw material moving device such as the vibration device 10 shown in FIG. 2, for example. Industrial applicability

As described above, according to the apparatus of the present invention, when charging the raw material such as iron oxide agglomerate into the rotary hearth furnace, the raw material is supplied from the inner peripheral side to the outer peripheral side of the hearth without complicating the apparatus. The amount can be uniform. Therefore, even when the processing scale is small, the raw material can be smoothly charged without clogging or catching of the raw material, and the processing temperature becomes uniform in the width direction of the hearth surface. In addition, the provision of a leveling tool allows the material on the charging device to be controlled to almost one layer, and the material tends to be one layer even on the hearth. For this reason, the temperature difference between the upper and lower parts of the raw material layer is small, and the reduction rate is almost constant, so that the productivity is improved.

Claims

The scope of the claims

1. In a raw material charging apparatus for a rotary hearth furnace for charging and heating and reducing a raw material in a hearth surface, one end of a bottom plate of the charging apparatus is fixed to a frame of the charging apparatus, and the other end. The opening end is formed in a shape connecting a plurality of continuous straight lines or curves. The plurality of continuous straight lines or curves are formed by imaginary lines obtained by dividing the hearth surface in the width direction, and the raw material movement of the charging device. A raw material charging apparatus for a rotary hearth furnace, wherein the raw material charging apparatus is a straight line or a curved line connecting intersections of straight lines parallel to the direction in order, and satisfying the condition (1).

A / a = B / b = C / c = D / d ... (1) A, B, C, D: Surface area when the hearth surface is divided in the width direction a, b, c, d ... The other bottom plate The projected length of each of the straight lines or curves at the ends in the direction perpendicular to the direction of material movement

2. The rotary hearth according to claim 1, wherein a leveling device for leveling the raw material to a uniform thickness is disposed between the frame of the charging device and an end of the bottom plate opening. Furnace raw material charging equipment.

3. The raw material charging apparatus for a rotary hearth furnace according to claim 1, wherein the charging apparatus is inclined at an angle of repose greater than or equal to the angle of repose of the raw material.

4. The raw material charging device for a rotary hearth furnace according to claim 1, wherein the charging device is disposed at a position smaller than the angle of repose of the raw material, and a raw material moving device is provided.