JP2504484Y2 - Electric melting furnace for rock wheels - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an electric melting furnace for rock wool.

[Conventional technology]

Rockwool melts its raw material in a melting furnace,
It is produced by tapping the molten raw material in a cotton maker and making it into fibers by a blowing method or a spinning method. As rock wool raw material, andesite, basalt, etc. have been used in the past, but recently, in order to stabilize the quality, metal slag, mainly blast furnace slag, was used as the main raw material and Where silica stone, dolomite, limestone, etc. are added as auxiliary raw materials for adjustment, an electric melting furnace is generally used as a melting furnace for rock wool raw materials. When a rockwool raw material whose main component is a raw material containing various iron oxides is melted, a part of the iron oxide in the rockwool raw material reacts with the carbon electrode and the carbon lining material inside the furnace in the molten state (reduction). Reaction) to produce pig iron,
This pig iron is stored in the furnace bottom as hot metal. Then, in the electric melting furnace, the tap hole for tapping the molten rock wool raw material into the cottonmaking machine is provided to some extent above the furnace bottom, but the amount of hot metal stored in the furnace bottom is the amount of raw material to be fed into the furnace. In order to increase with the repeated charging and melting,
When the bath surface of the hot metal reaches the tap hole, the hot metal is tapped together with the rock wool raw material into a cotton maker and the quality of the rock wool produced changes.

Therefore, in an electric melting furnace that melts a rockwool raw material containing iron oxide, it is necessary to remove the hot metal stored in the furnace bottom from the inside of the furnace before the bath surface reaches the tap of the molten raw material. For this reason, in the melting furnace, a hot metal outlet is provided separately from the tap of the molten raw material, and the hot metal stored in the furnace bottom is regularly withdrawn from the hot metal outlet. This hot metal outlet is conventionally provided at the same level as the furnace bottom or at a position lower than the furnace bottom (Japanese Patent Laid-Open No. 62-15314).
No. 0 and Japanese Utility Model Laid-Open No. 63-46437).

However, it was found that when the hot metal stored in the furnace bottom was completely removed, the carbon lining material provided in the furnace bottom was corroded by the molten rock wool raw material (iron oxide in the molten raw material). Due to the reduction reaction).

Therefore, in order to protect the carbon lining material at the bottom of the melting furnace from corrosion, an electric melting furnace has been considered in which a hot metal outlet is provided at a position higher than the bottom of the furnace to leave a certain amount of hot metal.

[Problems to be solved by the device]

However, in the electric melting furnace equipped with the hot metal outlet in this way, although the carbon liner at the bottom of the furnace is certainly protected by the hot metal, at the time of inspection and repair work of the furnace performed at regular intervals, the following Such inconvenience occurs.

That is, the inspection (repair) work involves stopping the supply of electric power to the electric melting furnace, cooling the furnace body, and then inspecting and repairing the carbon lining material on the furnace wall and the bottom of the furnace. The hot metal stored for protection cools and solidifies to cover the bottom of the furnace, so the hot metal that has solidified must be crushed and removed prior to inspection and repair of the furnace bottom. There is a problem of trouble.

The present invention has been made in view of the above situation,
The purpose is to always store hot metal of a certain depth in the bottom of the furnace during normal operation, and perform periodic or unscheduled inspections.
An object of the present invention is to provide an electric melting furnace for rock wool, which is capable of extracting all of the hot metal that has been stored during repair work.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a furnace body with a tap hole for molten rockwool raw material and a hot metal outlet for discharging hot metal stored in the furnace bottom, and the hot metal outlet is provided in a furnace. It is located at a position higher than the bottom and at the same level as the lowest part of the furnace bottom.

[Action]

By doing this, during normal operation, when the stored hot metal at the bottom of the furnace is extracted from the hot metal outlet, the hot metal below is removed from the hot metal outlet by removing it from the hot metal outlet provided at a position higher than the bottom of the furnace. Since it does not flow out and remains in the furnace, it allows the bottom of the furnace to be covered by a layer of hot metal remaining thereon. That is, the furnace bottom is protected so that the rockwool raw material does not come into contact with the carbon lining material on the furnace bottom by the hot metal left on the furnace bottom.

In addition, during regular or unscheduled inspection and repair work, if all of the hot metal pool is drained from the hot metal outlet provided in the lowest part of the furnace bottom, the necessary inspection and repair work can be performed easily. Become.

〔Example〕

The present invention will be described below based on the first embodiment shown in FIGS. 1 and 2.

In FIG. 1, 1 is a furnace body of an electric melting furnace, 2 is a furnace lid, and the furnace bottom and inner wall surface of the furnace body 1 are lined with a carbon lining material 1a. Reference numeral 3 is a tap hole for the molten rock wool material provided on the furnace wall of the furnace body 1. The tap hole 3 is provided at a position sufficiently high from the bottom of the furnace. Further, 4 and 4a are hot metal outlets provided on the furnace wall opposite to the tap hole 3. One of the hot metal outlets 4 and 4a
Is provided at a position slightly higher than the furnace bottom and sufficiently lower than the tap hole 3. The other hot metal outlet 4a is provided at the same level as the bottom of the furnace, or at the same level as the lowest part of the bottom, such as a slightly lower part. Further, the tap 3 is provided with a lid 3a that can be opened and closed. The hot metal outlets 4, 4a are closed by closing muds 5, 5a. To further describe this hot metal outlet 4, 4a,
In the present embodiment, a device equipped with a lifter-equipped mud gun (neither shown) is used, and the opening and closing operations of the melt outlets 4 and 4a are performed by the same mud gun-equipped mud gun. I am supposed to do it.

On the other hand, 6 is a plurality of carbon electrodes which are inserted into the furnace by penetrating the furnace lid 2. Each of the electrodes 6 is supported by a vertical mast 7 standing upright on the outside of the furnace body so as to be vertically movable. It is held at 8. Further, 9 and 10 are main raw material and auxiliary raw material charging pipes for charging rock wool raw material into the furnace, and these raw material charging pipes 9 and 10 are attached to the furnace lid 2. A hopper 9a is provided above the main raw material charging pipe 9, and a raw material containing iron oxide, which is the main raw material for rock wool, such as blast furnace slag (here, molten slag), is conveyed by a ladle 11 and is fed into the hopper. 9a, and is charged into the furnace through the main raw material insertion pipe 9. Further, 12 is an auxiliary raw material storage tank installed above the furnace, and 13 is an auxiliary raw material supply device for supplying the auxiliary raw material in the storage tank 12 to the auxiliary raw material charging pipe 10.

The operation of the electric melting furnace configured as described above will now be described. To melt the rock wool raw material, the rock wool raw material (main raw material and auxiliary raw material) is charged into the furnace, and the carbon electrode 6 is energized. In this case, when a large amount of molten blast furnace slag is charged as the main raw material from the start of operation of the electric melting furnace, cracks due to thermal shock may occur in the carbon lining material 1a at the bottom of the furnace, so at the start of operation , Charging the cooled blast furnace slag particles as a part or all of the main raw material, and charging a carbonaceous material (coke) for energization into the charging raw material,
It is desirable to gradually melt the charge. However, even in this case, when the molten rockwool raw material A is in direct contact with the carbon lining material 1a on the bottom of the furnace, the iron oxides in the molten raw material A, that is, carbon unsaturated iron, are contained in the carbon of the bottom of the furnace. Since the carbon lining material 1a at the furnace bottom may be eroded in order to cause a reduction reaction by absorbing carbon from the upholstery material 1a, prior to the charging of rock wool raw material, the carbon content is 3.5% or more. Crushed pig iron particles are spread on the bottom of the furnace, and rockwool raw material is charged on top of it. In other words, if you put crushed pig iron particles on the bottom of the furnace,
The crushed particles of pig iron are melted to form hot metal, and the layer of the hot metal covers the furnace bottom. Therefore, the iron oxide in the molten raw material A absorbs carbon from the carbon lining material 1a at the furnace bottom and causes a reduction reaction. Will be prevented.

On the other hand, after melting the rock wool raw material charged in the furnace, the spout lid 3b is opened and the molten raw material A in the furnace is tapped from the tap 3 to a cotton making machine (not shown). The charging of the rock wool raw material into the furnace and its melting are continued even after the molten raw material A starts to be discharged, and the molten raw material A is continuously discharged to the cotton maker.

When such an operation is carried out, pig iron produced as a result of a reaction (reduction reaction) with part of the iron oxide in the rockwool raw material in the molten state with the carbon electrode 6 and the carbon lining material 1a on the furnace wall becomes hot metal on the furnace bottom. Store it.

Here, in order to prevent the hot metal B stored in the furnace bottom from being tapped into the cottonmaking machine together with the rock wool raw material, the hot metal B stored in the furnace bottom is removed from the furnace before the bath surface reaches the tap hole 3. It is necessary to take it.

Therefore, when extracting the hot metal B stored in the furnace bottom, the closed mud 5 that closes the hot metal outlet 4 is removed to open the hot metal outlet 3, and the hot metal B at the furnace bottom is removed from the hot metal outlet 4. Just let it out.

However, since the hot metal outlet 4 is provided at a position higher than the bottom of the furnace, the hot metal above the level of the hot metal outlet 4 flows out from the hot metal outlet 4, but the hot metal below the level is shown in FIG. It will be left in the furnace as shown in. In addition,
The removal of the hot metal B is performed until the molten rock wool raw material A on the stored hot metal B flows out from the hot metal outlet 4. After the hot metal B is extracted, the hot metal outlet 4 is closed again with the closing mud 5.

Thus, in the above electric melting furnace, even if the molten hot metal B at the bottom of the furnace is taken out, the hot metal B below the level of the hot metal extraction port 4 remains in the furnace, so that the hot bottom layer is formed by the layer of hot metal remaining above it. Can be covered. Therefore, even after the hot metal extraction, it is possible to prevent iron oxide in the molten rock wool raw material, that is, carbon unsaturated iron, from absorbing carbon from the carbon lining material 1a at the bottom of the furnace and causing a reduction reaction. Corrosion of the bottom carbon lining material 1a can be reduced.

When inspection or repair work is required, the hot metal outlet 4a, which is at the same level as the lowest level of the bottom of the furnace, is always closed with the closing mud 5a, as shown in Fig. 2. Open with a mud gun and remove all the hot metal that has accumulated. Then, after that, if the furnace body 1 is cooled and the carbon lining material 1a on the furnace wall and the furnace bottom is inspected and repaired, necessary work can be easily performed.

Therefore, there is an effect that both normal operation and regular (or unscheduled) work can be compatible.

The invention is not limited to the first embodiment, but may be the second embodiment shown in FIG. 3 or the third embodiment shown in FIG.

That is, in the second embodiment, the hot metal outlet 4a is provided not only on the furnace side wall but also on the bottom wall of the furnace body 1 so that the hot metal flows from the furnace bottom to the outside through the bottom wall. is there.

The third embodiment is a modified example thereof, in which the hot metal outlet 4 on the side wall of the furnace is used.
And a hot metal outlet 4a at the bottom of the furnace.

In addition, in the first embodiment, the molten hot metal is extracted during the operation while continuously melting the rock wool raw material and tapping the molten raw material, but the removal of the accumulated hot metal is performed in the electric melting furnace. It may be carried out after the operation is stopped and the molten rock wool raw material in the furnace is tapped, and further, the present invention is a rotary type electric melting method in which the molten rock wool raw material in the furnace is tapped and tapped. Of course, it can be applied to a furnace.

[Effect of device]

As explained above, according to the present invention, during continuous operation,
Even if the hot metal is extracted from the hot metal outlet at a position higher than the bottom of the furnace, the hot metal below the level of the hot metal outlet remains in the furnace, and the furnace bottom is covered and protected by the amount of hot metal remaining on it.
Corrosion of the carbon liner on the bottom of the furnace can be reduced.

Moreover, at the time of inspection / repair, all of the hot metal that is stored can be extracted from the hot metal extraction port at the same level as the lowest position of the furnace bottom, so inspection / repair work can be facilitated.

[Brief description of drawings]

FIG. 1 and FIG. 2 are sectional views of an electric melting furnace in a raw material molten state and a hot metal extraction state showing a first embodiment of the present invention,
FIG. 3 is a sectional view showing an electric melting furnace according to a second embodiment of the present invention, and FIG. 4 is a sectional view showing an electric melting furnace according to a third embodiment of the present invention. 1 ... Furnace body, 1a ... Carbon liner, 3 ... Outlet, 4,4a ...
… Hot metal outlet, 5, 5a… Blocking mud, A… Molten raw material,
B ... hot metal.

Claims (1)

(57) [Scope of utility model registration request] 1. An electric melting furnace for melting a rockwool raw material containing iron oxide, wherein a furnace body is provided with a tap hole for the melted rockwool raw material and a hot metal outlet for discharging the hot metal stored in the furnace bottom. At the same time, the molten iron outlet is provided at a position higher than the furnace bottom and at the same level as the lowest part of the furnace bottom.