JP2000146452A - Fixed smelting furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixed smelting furnace which is easy in repairing the furnace, and capable of greatly shortening the furnace repairing time. SOLUTION: In a fixed smelting furnace 1 which is provided with a tap hole 13 in a furnace side wall and achieves the operation remaining a molten metal of a specified quantity in the furnace when the molten metal 19 in the furnace is discharged from the tap hole, a discharge hole 12 to discharge the molten metal remaining in the furnace is provided on a furnace bottom, and a furnace bottom part 3 in a range corresponding to 1/2 to 2/3 of the inside diameter of a shell 2 of the furnace body is detachable. A plurality of exhaust gas ducts 6 are preferably provided on the furnace top position where a part 5 of a furnace top is also detachable, a furnace repairing tower can be inserted, and the detachable part of the furnace top is not interfered with.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixed type smelting furnace used for smelting metals, and more particularly to a smelting furnace which can be easily repaired and can shorten the repairing period. is there.

[0002]

2. Description of the Related Art A smelting furnace has a fixed type such as a blast furnace, a converter,
There are two types of tilting type such as electric furnace, each of which is mainly
In a fixed smelting furnace, continuous smelting is performed in which raw materials are continuously charged and reaction products are discharged continuously or semi-continuously. Batch smelting in which a product is charged and discharged each time smelting is performed.

[0003] The smelting reduction smelting of iron ore is a continuous smelting in which the produced hot metal and molten slag are discharged continuously or intermittently outside the furnace. In this method, it is necessary to always secure an iron bath in the furnace in order to promote a reaction in the furnace, and a predetermined amount of hot metal is left in the furnace even during discharge. Therefore, a tap hole is generally provided on the furnace side wall, and operation is performed with a predetermined amount of molten iron remaining below the tap hole.

In the smelting reduction smelting, two types of smelting furnaces described above have been proposed.
198414 discloses a converter type tilting smelting reduction furnace in which a furnace body center portion is supported by trunnion bearings.
Japanese Patent Application Laid-Open No. 4-80311 discloses a shaft-shaped fixed smelting reduction furnace having a tap hole formed in a side wall portion of a lower portion of the furnace. However, in the tilting smelting reduction furnace, when the furnace shell becomes large, the supporting weight of the tilting support part such as the trunnion shaft increases, and the equipment increases in size to secure the mechanical strength of the support part, resulting in an increase in equipment cost. In addition, the size increase makes it difficult to arrange other accessory machines around the furnace. Furthermore, when a water-cooled metal panel is installed in the slag line section in the furnace, when the metal plate is tilted to bring hot metal into contact with the water-cooled panel, the water-cooled panel is melted and damaged. Can not. Therefore, at present, as a smelting reduction furnace for iron ore,
Fixed furnace bodies are more advantageous.

[0005]

However, when the work bricks constituting the furnace body are worn out and the life of the furnace has expired, if the furnace body is a tilting furnace body, the furnace body is tilted, and the molten iron remaining in the furnace and Molten slag can be discharged from the tap hole provided on the side wall.However, in a fixed furnace, the molten iron and molten slag must be cooled and solidified as in a blast furnace, then crushed and cut and discharged outside the furnace. Must. Therefore, a long cooling period is required, furnace repair is extended, and the operation rate is reduced. In addition, when the work bricks in the furnace are transshipped, materials such as bricks are supplied and discharged from the furnace top, so that furnace repair work is complicated and the furnace repair period is extended. As described above, the conventional furnace repair work involving the cooling and discharging work of the furnace residue has caused an increase in manufacturing cost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fixed smelting furnace capable of easily performing furnace repair and greatly shortening the furnace repair period. It is.

[0007]

According to a first aspect of the present invention, there is provided a fixed smelting furnace having a tap hole on a side wall of the furnace, and discharging a predetermined amount of molten metal in the furnace when the molten metal in the furnace is discharged from the tap hole. In the fixed type smelting furnace which is operated in the furnace, a discharge hole for discharging the molten metal remaining in the furnace is provided in the furnace bottom, and 1/2 to 2/3 of the inner diameter of the furnace shell. Is characterized in that the furnace bottom portion in a range corresponding to the above is removable.

[0008] In the fixed smelting furnace according to the second invention, in the first invention, a part of the furnace top is removable.
The furnace repair tower can be inserted through an opening formed by removing the removable portion.

A fixed smelting furnace according to a third invention is characterized in that, in the second invention, a plurality of exhaust gas ducts are provided at a furnace top position which does not interfere with a removable portion of the furnace top. It is.

The fixed smelting furnace according to a fourth aspect of the present invention is characterized in that, in the second aspect, an opening formed by removing a removable portion of the furnace top also serves as an opening for an exhaust gas duct. It is assumed that.

In the present invention, a discharge hole is provided at the bottom of the fixed smelting furnace. When furnace repair becomes necessary due to erosion of the work bricks of the fixed smelting furnace, the discharge hole provided at the furnace bottom is forcibly opened, and the molten metal or molten metal remaining in the furnace is removed. Drain slag. Therefore, it is not necessary to cool the inside of the furnace until the molten metal or the molten slag in the furnace solidifies, and the operation of discharging the metal or the slag solidified in the furnace is greatly reduced. As a result, the furnace repair period can be significantly reduced.

In the present invention, the inner diameter of the furnace shell is 1/2 to 2 /
The furnace bottom portion in a range corresponding to 3 is made removable, and this portion is removed during furnace repair to form an opening. Therefore, unnecessary materials such as removed bricks can be discharged to the outside of the furnace through the opening, so that furnace repair becomes extremely easy. Further, since the brick construction of the removed furnace bottom portion can be individually carried out offline, the entire furnace repair period can be shortened. In addition, the bottom blown tuyere is often installed in the removed furnace bottom, and by removing it from the furnace body and repairing it, the bottom blown tuyere can be easily replaced, which contributes to shortening the furnace repair period. At this time, if the size of the opening is less than 1/2 of the inner diameter of the furnace shell, it is too narrow to install all the tuyere, and there is a problem in taking out and carrying in the materials used for furnace repair. . As a size satisfying these, it is sufficient that the maximum is 2/3 of the inner diameter of the furnace shell.

Further, in the present invention, a removable portion is provided at the furnace top, and the furnace repair tower used at the time of furnace repair is provided in the furnace through an opening formed by removing this portion at the time of furnace repair. Since the furnace is repaired using the furnace repair tower, the furnace repair can be performed quickly. Since this part is sealed during operation, smelting in which the furnace pressure is higher than the atmospheric pressure is also possible. The furnace repair tower is provided with a breaker for peeling bricks in the furnace, a pallet transporter for raising and lowering materials such as bricks, a work table serving as a scaffold for brick construction, and the like.

By providing a plurality of exhaust gas ducts at the furnace top position which does not interfere with the removable part of the furnace top, it is not necessary to remove the exhaust gas duct when inserting the furnace repair tower into the furnace. Repair work can be performed quickly. Further, when the opening formed by removing the removable portion of the furnace top also serves as the opening for the exhaust gas duct, the equipment can be simplified and the equipment cost can be reduced.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 and 2 are schematic longitudinal sectional views of an iron ore smelting reduction furnace which is an example of an embodiment of a fixed smelting furnace according to the present invention. FIG. 1 shows a state during operation. FIG. 4 is a diagram showing a state during furnace repair.

1 and 2, the smelting reduction furnace 1 has a furnace shell 2 as an outer shell, and a permanent brick 9 and a work brick inside the furnace shell 2 on the furnace bottom and the side wall on the furnace bottom side. 10, refractories are installed in the order of 10, a metal water-cooling panel 14 is installed on the side wall inside the furnace shell 2, and two exhaust gas ducts 6, a duct 4 and a raw material inlet 21 are provided on the furnace top. A hood 5 is connected to the duct 4 so as to be separable from the duct 4, and the smelting reduction furnace 1 composed of these is fixed by a support member 8. The exhaust gas duct 6 is connected to a dust collector (not shown) and a pre-reduction furnace (not shown).

At the bottom of the furnace, a plurality of tuyere tuyeres 11 and one discharge hole 12 are provided, from which a stirring gas such as Ar or N ₂ can be blown. The discharge hole 12 is usually closed by a mud agent or the like,
Or it is used as a tuyere. The discharge hole 12
When it is closed by a mud agent or the like, by forcibly opening it from the outside of the furnace by a punch or the like, it is possible to discharge the hot metal 19 and the molten slag 20 remaining in the furnace,
When used as a tuyere, Ar or N ₂
Instead of stirring gas, etc., O ₂ is blown into the tuyere refractory to melt and enlarge the inner diameter, so that the hot metal 19 and the molten slag 20 remaining in the furnace can be discharged. Therefore, it is preferable that the discharge hole 12 is provided at the lowest part of the furnace bottom. The furnace bottom portion including the bottom blowing tuyere 11 and the discharge hole 12 is separable from the smelting reduction furnace 1, and this furnace bottom portion is hereinafter referred to as a furnace bottom exchange unit 3. Furnace bottom exchange part 3
Has a size of １ ／ to ／ of the inner diameter of the furnace shell 2. However, the hearth replacement part 3 does not need to have a circular shape, and the minimum width is equal to or more than の of the inner diameter of the furnace shell 2.
The maximum width may be a polygon not more than 2/3 of the inner diameter of the furnace shell 2.

A tap hole 13 filled with a mud agent (not shown) is provided in the refractory construction area of the side wall.
An upper-blown oxygen lance 15 is provided so as to be able to move up and down in the furnace through the hood 5 at the furnace top. Although not shown, the hood 5 and the top-blown oxygen lance 15 are sealed, so that the operation in which the furnace pressure of the smelting reduction furnace 1 is higher or lower than the atmospheric pressure can be performed.

In the smelting reduction smelting of iron ore using the smelting reduction furnace 1, while controlling the furnace pressure to 1.5 to 2.5 atmospheres,
Iron ore, coal, quicklime, and lightly burnt dolomite are charged through the raw material inlet 21, and oxygen is blown from the top blown oxygen lance 15, and nitrogen is blown from the bottom blown tuyere 11 to stir the hot metal 19 while stirring the hot metal 19. The stone is melt-reduced to produce hot metal 19 and molten slag 20. Before the hot metal 19 is produced in a predetermined amount and reaches the position of the water cooling panel 14,
3 is opened to discharge the hot metal 19 and the molten slag 20 to a hot metal holding vessel (not shown). Then, with a predetermined amount of the hot metal 19 remaining in the furnace, the tapping hole 13 is filled with a mud agent, the discharge is stopped, and the operation of the smelting reduction smelting is continued.

When the smelting reduction smelting operation is continued as described above and the work brick 10 is worn and reaches the standard remaining thickness, the molten iron 19 and the molten slag 20 are discharged from the tap 13 and the smelting reduction smelting is performed. Stop smelting and move to furnace repair. Prior to the furnace repair, the discharge hole 12 is opened from the outside of the furnace by a punch or the like, and the hot metal 19 and the molten slag 20 remaining in the furnace are discharged. After the discharge, the inside of the furnace is allowed to cool. Then, when the temperature in the furnace is reduced to a predetermined value, the top-blown oxygen lance 15 is
The hood 5 is removed from the duct 4 and the furnace repair tower 16 is inserted into the furnace from the furnace top through the opening formed. At this time, since the exhaust gas duct 6 is installed at a position where it does not interfere with the removal of the hood 5, that is, at a position where it does not interfere with the insertion of the furnace repair tower 16, the furnace repair tower 16 can be easily inserted. The reason for installing a plurality of exhaust gas ducts 6 is that the exhaust gas duct 6 is installed at the furnace top position which does not interfere with the work of removing the hood 5, so that a large-diameter exhaust gas duct 6 cannot be installed. This is for ensuring the cross-sectional area of the exhaust gas.

Next, joints between the hearth exchanging part 3 and the surroundings are cut off, the hearth exchanging part 3 is removed from the hearth, and is loaded on the bogie 17. A jack 18 is installed on the truck 17, and the furnace bottom exchanging section 3 can be lifted and received by the jack 18. Thereafter, the work brick 10, the tap 13 and the permanent brick 9 as necessary are removed from the furnace and replaced with a new one. The removed hearth replacement part 3 is
1, the discharge hole 12, and the work brick 10 are prepared offline, and the prepared hearth exchanging part 3 is installed in the furnace bottom in the reverse order of removal. Then, when the maintenance inside the furnace is completed, the furnace repair tower 16 is lifted and removed, and the hood 5 and the top blown oxygen lance 15 are attached to complete the furnace repair. After completion of the furnace repair, after performing an airtight test, test operation, etc., the furnace body is heated to resume smelting reduction smelting.

By making the structure of the smelting reduction furnace 1 in this way, the furnace repair becomes easy and the furnace repair period can be greatly shortened. Incidentally, according to the experience of the present inventors, the furnace repair period could be reduced to about half as compared with an integrated smelting reduction furnace having the same volume.

FIGS. 3 and 4 are schematic cross-sectional views of an iron ore smelting reduction furnace showing another embodiment of the fixed smelting furnace according to the present invention. FIG. FIG. 4
FIG. 4 is a diagram showing a state during furnace repair. 3 and FIG. 4, the same parts as those in FIG. 1 and FIG.
The description is omitted.

As shown in FIGS. 3 and 4, in the smelting reduction furnace 1, a duct 4 provided on the furnace top and an exhaust gas duct 7 are detachably connected, and further, the exhaust gas duct 7 and the exhaust gas duct 6 are connected. Removably connected. Then, an upper-blowing oxygen lance 15 is installed so as to be able to move up and down in the furnace through the exhaust gas duct 7. The exhaust gas duct 6 is connected to a dust collector (not shown) and a pre-reduction furnace (not shown).

Since the exhaust gas duct 7 can be separated from the duct 4 and the exhaust gas duct 6, at the time of furnace repair, first,
If the top blown oxygen lance 15 is withdrawn from the exhaust gas duct 7, and then the exhaust gas duct 7 is removed from the duct 4 and the exhaust gas duct 6, the furnace repair tower 1 is formed through the opening formed.
6 can be inserted into the furnace from the furnace top side.

As described above, the smelting reduction furnace 1 has a structure in which the opening for inserting the furnace repair tower 16 also serves as the opening for the exhaust gas duct 6, and the other structures are the same as those in FIGS. Therefore, furnace repair methods other than the smelting reduction smelting method and the method of inserting the furnace repair tower 16 are performed according to the above description, and the description thereof is omitted. Also in this smelting reduction furnace 1, furnace repair becomes easy, and the furnace repair period can be greatly reduced. Furthermore, since the number of exhaust gas ducts 6 can be reduced to one, the equipment can be simplified and the equipment cost can be reduced.

In the above description, the iron ore smelting reduction furnace 1 has been described as a fixed smelting furnace. However, the fixed smelting furnace is not limited to the smelting reduction furnace 1, but oxygen is blown to continuously feed iron scrap. Iron melting furnace that melts
The present invention can be similarly applied to a smelting furnace that blows oxygen and reduces Ni ore or Cr ore with coke to produce Fe—Ni alloy and Fe—Cr alloy in a molten state.

[0028]

According to the present invention, furnace repair in a fixed smelting furnace is simplified, and the furnace repair period is greatly shortened, so that furnace repair costs can be reduced. In addition, since the operation rate of the fixed smelting furnace is improved, the production cost can be reduced, and the industrial effect is outstanding.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a smelting reduction furnace as an example of the present invention during operation.

FIG. 2 is a schematic longitudinal sectional view of a smelting reduction furnace as one example of the present invention during furnace repair.

FIG. 3 is a schematic longitudinal sectional view of a smelting reduction furnace according to another embodiment of the present invention during operation.

FIG. 4 is a schematic longitudinal sectional view of a smelting reduction furnace as another example of the present invention during furnace repair.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Smelting reduction furnace 2 Furnace shell 3 Furnace bottom exchange part 4 Duct 5 Hood 6 Exhaust gas duct 7 Exhaust gas duct 11 Bottom blowing tuyere 12 Discharge hole 13 Hot water outlet 14 Water cooling panel 15 Top blowing oxygen lance 16 Furnace repair tower 17 Dolly 19 Hot metal 20 molten slag

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeshi Sekiguchi 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Masahiro Kawakami 1-2-1-2 Marunouchi, Chiyoda-ku, Tokyo Sun (72) Inventor Susumu Isozaki, 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Nippon Steel Pipe Co., Ltd. (72) Katsuhiro Iwasaki 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan F-term (reference) in Steel Pipe Co., Ltd. 4K012 CA08 4K045 AA01 AA03 BA02 GA06 GA11 4K051 AA00 AB05 BA01 BB00 DA00 EA00

Claims (4)

[Claims] 1. A fixed smelting furnace having a tap hole on a side wall of a furnace and performing an operation in which a predetermined amount of molten metal remains in the furnace when the molten metal in the furnace is discharged from the tap hole. A discharge hole for discharging the molten metal remaining in the furnace is provided in the furnace bottom, and a furnace bottom portion corresponding to 1/2 to 2/3 of the inner diameter of the furnace shell is removable. And fixed smelting furnace. 2. A part of the furnace top is removable,
The fixed smelting furnace according to claim 1, wherein the furnace repair tower can be inserted through an opening formed by removing the removable portion. 3. The fixed smelting furnace according to claim 2, wherein a plurality of exhaust gas ducts are provided at a furnace top position that does not interfere with a removable portion of the furnace top. 4. The fixed smelting furnace according to claim 2, wherein an opening formed by removing a removable portion of the furnace top also serves as an opening for an exhaust gas duct.