JPH0754281Y2 - Smelting reduction furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a metal bath furnace type smelting reduction furnace for reducing iron ore or the like in a molten state.

[Prior Art] The smelting reduction method is a method of obtaining an iron or ferroalloy by reducing an ore containing a metal oxide such as iron ore (iron oxide) in a molten state, and is an alternative to the blast furnace method. It is a technology that has attracted attention in recent years.

Various processes have been proposed for the smelting reduction method, and there are various types of reducing furnaces, but a typical type is a so-called metal bath furnace type smelting reduction furnace. For ironmaking, for example, molten iron (or iron bath including slag bath) is charged with iron ore (or ore such as pre-reduced iron) together with coal, lime and oxygen, and this is reduced to produce molten pig iron. Although it is a reducing furnace, it is used in many processes because of its fast reaction and simple equipment type.

Since a metal bath furnace type smelting reduction furnace is common with a converter which is a refining furnace for molten steel in that it holds molten metal, conventionally, a tiltable converter furnace 51 as shown in FIG. 6 has been used. It was common. In addition, the same type of smelting reduction furnace is, for example,
No. 903. Another reason why the converter furnace is used as the smelting reduction furnace is that in the smelting reduction method, the work is originally a batch type, and as shown in FIG. It is necessary to inject hot water (molten metal), and to inject this hot water using a ladle 52 etc.,
The fact that the furnace 51 can be tilted makes the injection work easier, and it is easy to take out the reduced molten metal from the furnace 51 by tilting the furnace 51.

As in the case of the converter, there is an opening (furnace opening) at the axial center position above the furnace body, and a flue (duct) 54 is connected to this through an elevating head 53 and the furnace is connected. The gas generated inside 51 is discharged. This is because a large amount of CO (carbon monoxide) gas, which has reducing power at high temperature, is generated in the furnace at the time of reduction, so this gas is sent to treatment equipment or iron ore before being put into the smelting reduction furnace. This is because it is used for pre-reduction of iron ore by leading it to the charged pre-reduction furnace. Further, since the gas contains combustible components, it rapidly burns when it comes into contact with oxygen in the air. Therefore, equipment for injecting an inert gas such as nitrogen gas is provided in the flue and the furnace body.

[Problems to be Solved by the Invention] However, the above-mentioned converter-type smelting reduction furnace has the following problems. That is, (a) when tilting the furnace, the head that connects the furnace mouth and the flue can be raised by a remote operation so that the head can be raised (for example,
It is necessary to use Japanese Patent Laid-Open No. 1-252891). For this reason, the structure of the head becomes complicated, the equipment cost is enormous, the head is easily broken, and the maintenance is troublesome.

(B) When the molten metal is injected, the furnace and the flue are completely separated from each other, so that the gas in the furnace escapes to the outside and air is mixed in the flue. Therefore, the recovery rate of the gas decreases, it cannot be effectively used for preliminary reduction, etc., and it is necessary to purge the air mixed in the flue and the furnace with an inert gas after injecting the molten metal into the furnace. is there. Since a large amount of inert gas is required for this purging, it is costly and also takes time (usually 20 to 30 minutes), resulting in a low operating rate.

The present invention has been made to solve the above-mentioned problems, and enables the molten metal to be injected and the reduced molten metal to be discharged without tilting the furnace so that the furnace and the flue are always connected. The cost can be reduced by omitting the head or simplifying the structure, and the facility cost can be significantly reduced. Also, it is not necessary to purge the air with an inert gas after injecting the molten metal, improving the operation rate. The purpose is to provide a smelting reduction furnace that can be used.

[Means for Solving the Problems] In order to achieve the above object, the smelting reduction furnace of the present invention is
a) connecting the flue to the furnace mouth directly or via the head,
b) a tap hole that can be opened and closed is provided at the bottom of the furnace, c) a molten metal injection hole is opened at the top of the furnace or a flue, and d) a molten metal injection part is connected to the injection hole, e) A blocking mechanism is provided between the injection hole and the injection section or at the receiving port of the injection section.

Further, as described in claim 2, f) a molten metal storage tank is provided between the injection hole and the injection portion with a closing mechanism interposed therebetween, and g) a high-pressure inert gas in the storage tank. It is preferable to connect a gas introduction pipe.

[Operation] According to the smelting reduction furnace of the present invention having the above-mentioned configuration, for example, in a furnace having a closing mechanism only on the inlet side of the injection part, an inert gas such as nitrogen gas is blown into the furnace to Make the inside a little higher than atmospheric pressure. Then, the closing mechanism is opened to inject the molten metal into the pouring portion, and the closing mechanism is closed to close the pouring portion to slightly lower the pressure of the furnace and inject the molten metal into the furnace. Thus, in the state where the molten metal as the seed water is injected into the furnace, the ore as the raw material is charged into the furnace together with the auxiliary raw material such as coal, and oxygen is blown to reduce the molten ore in the molten state. When the reduction work is completed, the tap hole at the bottom of the furnace is opened with a hole opener or the like, and tap water is tapped.
As a result, it is not necessary to attach or detach the head for connecting the furnace and the flue to the furnace mouth or to move up and down, and it is not necessary to purge the air flowing into the flue or the furnace with an inert gas.

According to the smelting reduction furnace of claim 2, in a state where the closing mechanism between the storage tank and the injection hole is closed, the closing mechanism between the injection part and the injection portion is opened, and the inert gas is blown into the tank. After purging the air, the molten metal is injected into the tank from the injection part. Then, the closing mechanism on the injection part side is closed, the closing mechanism on the injection hole side is opened, and the molten metal in the tank is injected into the furnace. As a result, the molten metal is injected into the furnace with the furnace completely isolated from the outside.

[Embodiment] An embodiment of the smelting reduction furnace of the present invention will be described below with reference to the drawings.

FIG. 1 is a smelting reduction system diagram for iron making equipped with the smelting reduction furnace of the present invention. In the figure, both the smelting reduction furnace 1 and the preliminary reduction furnace 25 are fixed type furnaces, not tilting type furnaces. After preliminary reduction of iron ore in a solid state in the preliminary reduction furnace 25, final reduction in a molten state is performed in the smelting reduction furnace 1. While performing reduction, smelting reduction furnace 1
In addition to the main system that introduces a part of the high-temperature reducing gas generated in the preliminary reduction furnace 25, the gas that has flowed out of the preliminary reduction furnace 25 is removed through the dust collector 30 to remove dust, and then the gas holder It has a storage system at 31.

Although the smelting reduction furnace 1 has a converter shape, it is a fixed type furnace having no tilting device as described above, and a refractory material is attached to the inner surface thereof. A tap hole 2 is formed near the bottom of the furnace 1, and normally (except when tapping) is closed with a plug (mud) like the conventional blast furnace tap, but by opening with a hole opener, etc. It can be opened and tapped when necessary.

The flue 4 is directly connected to the furnace opening 3 at the upper end of the smelting reduction furnace 1,
A lance 5 penetrates the flue 4 and is inserted in the axial center position of the smelting reduction furnace 1. A nitrogen gas blowing nozzle 6 for stirring the pig iron bath B is provided at the bottom of the furnace 1, and a nitrogen gas introducing pipe 7 for purging is connected to the upper end of the furnace 1.

An injection hole 8 for molten iron (seed bath) A is formed in the upper portion of the smelting reduction furnace 1. Further, a charging path 9 for the iron ore preliminarily reduced in the preliminary reduction furnace 25 and a charging path for coal, lime, etc.
10 are each connected to the top of the furnace 1.

11 is an injection part of molten iron A, and this injection part 11 is
The funnel-shaped injection container is provided with a closed lid 12 as a closing mechanism at the upper end opening. The lower end outlet of the injection container 11 is connected to the injection hole 8 via an injection pipe 13. Infusion container
A high-pressure nitrogen gas introduction pipe 14 and an exhaust pipe 15 equipped with an opening / closing valve 15a are connected to the upper end of 11.

In the smelting reduction furnace of this embodiment having the above-mentioned configuration, the smelting reduction iron-making method is carried out as follows.

First, at the time of startup, nitrogen gas is blown into the furnace 1 so that the inside of the furnace 1 is slightly higher than atmospheric pressure. Then, the sealing lid 12 is opened to inject the molten iron A into the injection container 11, and then the sealing lid 12 is closed to seal the inside of the injection container 11. In this state,
The pressure of the furnace 1 is slightly lowered and the molten iron A in the injection container 11 is injected into the furnace 1. In this way, in a state where the furnace 1 and the outside world are cut off, molten iron A as seed water is injected into the furnace 1, and then iron ore, coal, lime, etc. are charged into the furnace 1, and the lance 5
Blows in oxygen to start operation. That is, oxygen is blown from the lance 5, and the iron ore is reduced in a molten state to become pig iron. A high-temperature gas containing a large amount of CO and having a reducing power is generated along with the reduction reaction, but this gas passes through the flue 4 and most of it is dusted by the cyclone 24 and introduced into the preliminary reduction furnace 25. , Used for preliminary reduction of iron ore. The remaining gas is stored in the gas holder 31 and used as fuel after the dust is removed by the dust collector 30.

When the amount of pig iron (molten state) B in the furnace 1 reaches a predetermined amount, the tap hole 2 is opened by a hole opener, and the pig iron B and the molten slag C are tapped. After tapping, the mud gun fills the tap hole 2 with a blocking material such as a mud to close the tap hole 2.

In the above-mentioned embodiment, nitrogen gas is blown into the furnace 1 before the molten iron A is injected, but this is performed to make the internal pressure of the furnace 1 slightly higher than the atmospheric pressure in order to prevent the invasion of air from the injection container 11. However, the blowing time and amount of nitrogen gas are short.

FIG. 2 shows a smelting reduction furnace according to a second embodiment of the present invention. The difference between the furnace 1a of this embodiment and the furnace 1 of the above embodiment is the structure of the molten metal injection part 11a. thing,
And without using the lance 5 for blowing oxygen into the furnace 1a,
That is, the blowing nozzle 16 is used. Injection part
11a, as shown in the figure, consists of a funnel-shaped injector with an open upper end, and by lowering the ladle stopper type rod 17 as a closing mechanism and inserting the lower end into the outlet 17 'of the injector 11a. The outlet 17 'can be opened by closing the outlet 17' and raising the rod 17. Since other configurations are common to the furnace 1 of the above-described embodiment, common members are shown in FIG. 2 with the same reference numerals used in FIG. 1, and description thereof is omitted.

In the smelting reduction furnace 1a of the second embodiment, the molten metal A furnace 1a
The injection into the inside is performed as follows. That is, with the rod 17 closing the outlet 17 'of the injector 11a, nitrogen gas is blown into the furnace 1a to pressurize it and the injector 11a
A predetermined amount of molten metal A is injected into. Then, the rod 17 is lifted to open the outlet 17 ', and the molten metal A as the seed water is heated in the furnace.
Inject into 1a. At this time, since the outlet 17 'is blocked by the molten metal A and the pressure in the furnace 1a is increased to the atmospheric pressure or higher by the nitrogen gas, a part of the nitrogen gas is discharged from the outlet 17' and the molten metal. Although it is discharged from the inside of A to the outside, invasion of air into the furnace 1a is surely prevented. Thus, when the molten metal A remains in the injector 11a and the rod 17 is lowered to close the outlet 17 ', contact between the inside of the furnace 1a and the outside (air) is prevented, and the molten metal A is blocked. Can be injected into the furnace 1a.

FIG. 3 shows a smelting reduction furnace according to a third embodiment of the present invention. The difference between the furnace 1b of this embodiment and the furnace 1 of the first embodiment is that the injection part 11b of the molten metal A is The structure is different, and the furnace port 3 and the flue 4 are connected via a head 4 '. The injection part 11b, as shown in the figure,
It consists of a funnel-shaped injection container with a closed lid 12 at the top opening,
The outlet of the injection container 11b is connected to the injection hole 8 of the furnace 1b through a siphon-type closed pipe 18 having a substantially U shape. Since other configurations are common to those of the furnace 1 of the above-mentioned embodiment, common members are shown in FIG. 3 by using the reference numerals used in FIG. 1, and description thereof is omitted.

Injecting molten metal into the furnace 1b in the smelting reduction furnace 1b of the third embodiment, nitrogen gas is blown into the furnace 1b to pressurize it, the sealing lid 12 is opened, and a predetermined amount of molten metal A is injected into the injection container 11b. Inject. The injected molten metal A is a siphon-type closed tube.
The inside of the furnace 1b and the inside of the injection container 11b are shut off by filling the inside of the furnace 18. When the pressure in the furnace 1b is lowered after closing the sealing lid 12, the molten metal A in the injection container 11b is injected into the furnace 1b. At this time, the upper end opening of the injection container 11b is sealed with the sealing lid 12,
Further, since its outlet is also closed with the molten metal A filling the inside of the siphon type closed pipe 18, the invasion of air into the furnace 1b is surely prevented. Further, even if all the molten metal A in the injection container 11b is injected, the closed pipe 18 is filled with the molten metal A, so that the injection container 11b and the furnace 1b are always shut off.

FIG. 4 shows a smelting reduction furnace 1c according to a fourth embodiment of the present invention.
An injection hole 8'is formed in the flue 4 to inject the molten metal A into the injector 11c.
Is connected to the injection hole 8'of the flue 4, which is different from the furnace 1a of the second embodiment. The injector 11c in the figure
The valve portion (closure mechanism) 17c on the outlet side of is actually a combination of the ladle stopper type rod 17 shown in the second embodiment (FIG. 2) and the outlet 17 'to which this tip end fits. Alternatively, the siphon type closed tube 18 shown in the third embodiment (FIG. 3) is used.

FIG. 5 shows a smelting reduction furnace 1d according to a fifth embodiment of the present invention. As shown in the figure, in this embodiment, a storage tank 19 for the molten metal A is provided between the funnel-shaped injector 11d and the injection hole 8 of the furnace 1d with a closing mechanism interposed therebetween. The upper part of the valve part (blocking mechanism) in the figure
17d is a combination of the ladle stopper type rod 17 shown in the second embodiment (Fig. 2) and the outlet 17 'into which this tip end fits, and the lower side 18d is the third embodiment (third embodiment). The siphon-type closed pipe 18 shown in FIG. 3) is used.

In the smelting reduction furnace 1d of this embodiment, the storage tank 19 and the injection hole 8
After closing the valve portion 18d between and, open the valve portion 17d between the injector 11d, after blowing high pressure nitrogen gas from the nitrogen gas introduction pipe 14 into the storage tank 19 to purge the air. The molten metal A is injected into the storage tank 19 from the funnel-shaped injector 11d. And the valve portion 17d on the injector 11d side
Is closed, the valve portion 18d on the injection hole 7 side is opened, and the molten metal A in the storage tank 19 is injected into the furnace 1d. Therefore, the molten metal A as the seed water in the smelting reduction furnace 1d of this embodiment is injected into the furnace 1d in a state of being completely cut off from the outside.

As a means for isolating the smelting reduction furnace 1 and the molten metal injection part 11, instead of the rod 17 (Fig. 2) and the siphon-type closed pipe 18 (Fig. 3), opening and closing by a mud gun hole opener. A part may be provided in the injection port 8. The same smelting reduction furnace can be used not only for smelting reduction for iron making but also for smelting reduction of other metals such as obtaining ferrochrome from chromium ore.

[Effects of the Invention] According to the smelting reduction furnace of the present invention, the following effects are brought about.

(1) Since the molten metal can be injected and the reduced molten metal can be tapped without tilting the furnace, the head for connecting the furnace and the flue can be omitted, or the conventional converter furnace can be used. The structure can be simplified compared to the head, and the tilting device of the furnace is not required, so that the facility cost can be significantly reduced. Further, unlike the conventional furnace, it is not necessary to disconnect the furnace and the flue each time the molten metal (seed water) is injected, so the operation rate is greatly improved.

(2) For the same reason as (1) above, it is not necessary to purge the air and gas in the flue every time the molten metal is injected,
It is economical because the time required for purging can be shortened, the operating rate can be improved, and a large amount of inert gas for purging is not required. Moreover, since air is not mixed in the furnace and the flue, it is possible to reliably prevent rapid combustion due to contact between high-temperature reducing gas having a combustible component generated in the furnace due to smelting reduction and oxygen in the air. The safety is improved, and the reducing gas is hardly released to the outside of the furnace, and the recovery rate is improved. Therefore, the reducing gas can be effectively used for preliminary reduction and fuel.

(3) According to the smelting reduction furnace of the second aspect, the molten metal can be injected into the furnace in a state where the furnace and the external environment are completely cut off.

[Brief description of drawings]

FIG. 1 is a smelting reduction system diagram for iron making equipped with the smelting reduction furnace of the present invention. 2 is a sectional view showing a smelting reduction furnace according to a second embodiment of the present invention, FIG. 3 is a sectional view showing a smelting reduction furnace according to a third embodiment of the present invention, and FIG. 4 is a sectional view showing the present invention. Four
FIG. 5 is a sectional view showing a smelting reduction furnace according to an embodiment, and FIG. 5 is a sectional view showing a smelting reduction furnace according to a fifth embodiment of the present invention. FIG. 6 is a sectional view showing a conventional converter-type smelting reduction furnace. 1, 1a, 1b, 1c, 1d ... Smelting reduction furnace (fixed type furnace), 2 ... Tap hole, 3 ... Furnace opening, 4 ... Flue, 5 ... Lance, 8 ... Injection hole,
11, 11a, 11b, 11c, 11d ... Injection part, 12, 17, 18 ... Closure mechanism, 19 ... Storage tank.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichi Yajima, 3-1, 1-1 Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo Prefecture Kawasaki Heavy Industries, Ltd. Kobe factory (72) Ken Ken Takiura Higashi-kawasaki, Chuo-ku, Kobe-shi, Hyogo 3-1-1, Kawasaki Heavy Industries, Ltd. Kobe factory (72) Inventor Satoshi Tatsuda 3-1-1, Higashikawasaki-cho, Chuo-ku, Kobe, Hyogo Prefecture 1-1, Kawasaki Heavy Industries Ltd. (72) Inventor, Yukihiko Takaza 3-1, 1-1 Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo Inside the Kawasaki Heavy Industries, Ltd. Kobe factory (72) Inventor: Sumio Sato 3-1-1, Higashi-kawasaki-cho, Chuo-ku, Kobe, Hyogo Prefecture Inside the Kobe factory, Kawasaki Heavy Industries, Ltd.

Claims (2)

[Scope of utility model registration request] 1. A metal-bath furnace type smelting reduction furnace for charging ore as a raw material together with an auxiliary raw material such as coal into a molten metal bath in the furnace, and blowing oxygen into the molten metal for reduction in a molten state. A flue is connected to the furnace mouth of the furnace directly or through a head, a tap hole that can be opened and closed is provided at the bottom of the furnace, and a molten metal injection hole is opened at the top of the furnace or the flue. A smelting reduction furnace characterized in that a molten metal injection part is connected to the injection hole, and a closing mechanism is provided between the injection hole and the injection part or at a receiving port of the injection part. 2. A molten metal storage tank is provided between the injection hole and the injection portion with a closing mechanism interposed therebetween.
The smelting reduction furnace according to claim 1, wherein a high-pressure inert gas introduction pipe is connected to the storage tank.