JPH0362656B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention involves charging molten slag into a melting furnace, adding and mixing a composition adjusting material to the molten slag, and heating and maintaining the molten slag at a constant temperature. This invention relates to a method for extracting hot metal from inside the furnace in the operation of a melting furnace that produces rock wool by discharging the melt in portions.

[Conventional technology]

High-temperature molten slag, which is a large amount of by-product from blast furnaces in steel plants, is rapidly cooled and crushed with water and processed into granulated slag, which can be used as blast furnace cement, cement mixtures, ground improvement materials, concrete aggregates, etc. It's being used. In addition, this slag is discharged onto a vast site, cooled, and processed into crushed slag (slow-cooled slag), which is used not only as roadbed material, aggregate, and landfill material, but also as a raw material for rock wool.

To manufacture rock wool, component adjustment materials are added to crushed slag stone as necessary, the mixture is remelted in a melting furnace such as an electric furnace or cupola, and the molten material is fed to a cotton mill.
A method of forming fibers using centrifugal force and/or fluid pressure such as pressurized air or steam has been adopted. This conventional method uses crushed slag stone, which is convenient for transporting and storing raw materials, and it is also easy to adjust the chemical composition of rock wool raw materials, but the huge amount of heat taken out of the blast furnace is released during cooling and cannot be used. , resulting in them being discarded. Therefore, from the viewpoint of energy saving, a method of directly charging high-temperature molten slag from a blast furnace into an electric furnace, adjusting the composition and temperature, and then supplying the slag to a cotton mill is attracting attention. For example, Tokko Akira
It is described in JP-A No. 37-4559, JP-A-51-84929, JP-A-59-131534, etc.

In the former method, which uses crushed slag from Kyupora, etc., a remelting process is involved, so it is usually a batch method, and even if the iron content in the blast furnace slag accumulates at the bottom of the furnace, it is only for one batch, and the quantity is also small. Very little,
In cases where the discharge port is located at the lower end, a method is used in which slag containing iron is initially discharged and removed separately. In these steps, since there is no reducing action in the furnace, there is no action of reducing iron oxide in the slag to iron. Therefore, the removal of iron content was not so much of a technical problem.

In the latter method, in which rock wool is produced by receiving molten slag in an electric furnace or the like and adjusting the composition and heating temperature, not only the iron in the slag but also the components contained as iron oxide are removed by the electric furnace's carbon electrode, etc. It undergoes a reducing action and becomes molten iron, which is stored at the bottom. Moreover, in this process, blast furnace slag is received batchwise, but the molten material in the furnace flows out continuously, so the iron content in the slag and the iron content reduced by iron oxide are
If it flows out with the effluent, it will damage the quality of the fiber. If the molten metal is discharged not from the bottom of the furnace, but from the discharge port above, the molten metal will gradually accumulate at the bottom of the furnace. As described in JP-A-51-88728, in the method of tilting the melting furnace and discharging the tundish from the top, the iron accumulated at the bottom of the furnace is removed by not discharging the furnace to the end. In addition, special public relations
In Publication No. 37929, on the contrary, using this stored iron bath,
Heating is accomplished by induction heating or by blowing additives through a metal bath. In such a case, of course, there is no description of how to extract the hot metal.

[Problem that the invention seeks to solve]

This is not a method in which molten slag is charged into an electric furnace, a composition adjusting material such as silica stone is added, and the heating temperature is adjusted, and then the furnace is tilted and discharged from the top, nor is it discharged from the bottom of the furnace. A substantially constant amount is flowed out per hour from the outlet slightly above it,
In a system where molten slag is supplied directly to the cotton mill without going through a separate transfer furnace or tundish, the molten slag is intermittently supplied, but if the outflow is continuous, the iron content and iron oxide in the slag become electrically The hot metal reduced in the furnace gradually accumulates at the lowest end of the furnace. When this gradually accumulates and reaches the height of the outlet, it flows out together with the molten raw material, causing serious problems in cotton manufacturing. The present invention has been made to solve this problem.

[Means for solving problems]

In the present invention, molten slag is charged into a melting furnace, its composition is adjusted, and while the furnace is heated to a certain temperature range, the furnace is tilted and a substantially constant amount of molten slag is poured out from an outlet slightly above the bottom of the furnace. In the operation of an electric furnace that produces rock wool by discharging it, there is a
A taphole that can be drilled with a hole drill and is normally closed with a plug is installed, and the hole is drilled with a hole drill every time a certain amount of molten slag is processed, and the hot metal accumulated at the bottom of the furnace is extracted.
This is a method for extracting hot metal from a rock wool raw material melt, which involves subsequently pushing a mat into the opening and closing it.

To remove the hot metal after opening the hole, if the raw material outlet to the cotton mill is high enough above the furnace bottom to store enough hot metal, the melting furnace should be placed in an upright position or on the cotton mill side or the opposite side. This can be done by opening a tap hole even in a tilted state, but if the outlet is not that high from the bottom of the furnace and cannot store a large amount of hot metal, after opening the hole, the furnace body can be opened on the outflow side to the cotton milling machine. If the tip is tilted in the opposite direction, the hot metal can be extracted properly.

It goes without saying that this method cannot be applied to a method in which the molten raw material is constantly extracted from the lowest part of the furnace, since the molten metal will also flow out from time to time. In addition, compared to the method in which the molten metal is poured from the upper end into the tundish or relay furnace by tilting, it is sufficient to flow the molten metal from the upper end into a container other than the tundish or relay furnace once the molten metal has accumulated to a certain extent. is also not applicable.

The present invention employs a method in which the melting furnace is tilted to allow the melt to flow out in substantially constant amounts through the outlet slightly above the bottom of the furnace (preferably at a position 30 to 40% below the depth of the liquid). This is an effective method for In this case, the hot metal in the blast furnace slag and the hot metal produced by reducing iron oxide in the electric furnace accumulate at the bottom of the furnace as the throughput increases. It is clear that high-quality rock wool cannot be produced if this is poured into the cotton mill along with the melt. In the present invention, a tilting device is used to flow out a fixed amount of the melt, and a hole can be made with a hole puncher on the side wall of the bottom of the furnace, which is opposite to the melt outlet and the center of the furnace. A taphole that is normally closed with a plug is installed, and a hole is opened with a hole puncher every time a certain amount of molten slag is processed, and the hot metal stored at the bottom of the furnace is extracted. It is pushed in and closed.

When it is necessary to extract hot metal before it accumulates at the bottom of the furnace, the furnace body is tilted in the opposite direction to the outflow side to the cotton milling machine to remove the hot metal, thereby minimizing the loss of raw materials in the furnace. Only the hot metal can be extracted.

Next, the drawings will be explained. The figure is a longitudinal sectional view of an electric furnace suitable for carrying out the method of the present invention.
1 is an electric furnace main body, 2 is an electrode, 3 is a stirring gas introduction pipe, 4 is a blast furnace slag charging port, 5 is a charging device thereof,
6 is a stopper, and 7 is a ladle car for transporting blast furnace slag. Reference numeral 8 denotes a charging pipe for a component adjusting material such as preheated silica stone. 9 is an outlet for rock wool raw material melt; 1
0 is a cotton machine. 11 is a curved smooth surface attached to the lower part of the electric furnace; 12 is a guide roller that rotates in contact with the smooth surface 11; 13 is a base; 14 is a load cell that supports the base 13 at four locations; Measure the entire weight. 15 is a fluid cylinder for tilting the electric furnace, and 16 is its piston. 17 is a raw material melt inside, and 18 is hot metal stored at the bottom. Reference numeral 19 is a hole punching machine used in the present invention, and the electric furnace main body 1 is normally closed with a plug or the like.
The opening part 20 is opened by determining the time when the hot metal 18 is stored in the furnace from the amount of blast furnace slag processed.At this time, by tilting the furnace to the left,
Hot metal 18 is discharged. When all of the stored hot metal 18 is discharged and the effluent turns into molten slag, the mud is pushed into the hole-opening machine 20 using a plugging machine such as a mud gun to close it. Of course, in actual operation, it is most preferable to move the hole slightly to the left and collect the molten metal in the left corner before opening the hole.

[Effect]

Instead of pouring out from the upper end of the furnace, the hot metal settles to the bottom of the molten raw material and is extracted from the bottom, so the separation is clear and there is no waste of molten raw material being discharged along with the molten pig iron. . Raw materials are constantly discharged from the outlet slightly above the bottom of the furnace.
Despite the tilting method, there is no chance of molten metal getting mixed into the raw material. In addition, since the entire furnace is tilted, only the hot metal can be discharged more efficiently than when holes are opened at the bottom of the furnace, and the tilting device for discharging raw materials can be used in the opposite direction. This made it possible to directly supply the surface-making machine from the electric furnace without going through any relay furnaces such as those for hot metal separation.

〔Example〕

100 parts by weight of blast furnace slag was charged into an electric furnace, and preheated silica stone was charged and stirred. Heating it in an electric furnace,
Start tilting the furnace from within the standard temperature range of 1470±20℃, and melt the raw material at a substantially constant rate per hour from the outlet at a range of 30 to 40% below the depth of the liquid from the bottom of the furnace. The material was fed to a cotton mill to produce rock wool. When the charging amount reached 75 parts by weight, the furnace was made to stand upright, 25 parts by weight of blast furnace slag transported from the blast furnace in a pot truck was charged, the preheated silica stone was additionally stirred, and the furnace was tilted again. I started and repeated this.

After 500 tons of blast furnace slag has been processed, a hole is drilled at the bottom of the furnace on the opposite side of the outlet from the center of the furnace using a hole puncher, and the furnace is tilted backwards in this direction to extract approximately 1 ton of stored hot metal. Ivy.

〔effect〕

As explained above, according to the method of the present invention, since the molten slag whose composition has been adjusted is not discharged from the uppermost end of the furnace, it has the advantage of not requiring a relay furnace such as a tundish in the middle. In addition, in the method of discharging from the lowest part of the furnace, hot metal in the slag,
The hot metal produced by the reduction of iron oxide would flow out together with the slag, causing a serious hindrance to the cotton milling operation, but this does not occur. As described above, this method has advantages over other conventional methods, but since the hot metal has no outlet, it accumulates at the bottom of the furnace during processing of a large amount of molten slag, and eventually rises to the height of the discharge port. There is a risk of reaching When using the method of the present invention, the tilting device of the furnace body is used in the opposite direction, and a tap hole is opened in the side wall of the furnace bottom to extract hot metal every time a certain amount of slag is processed, so that continuous production is possible. This has the great effect of allowing continuous cotton-making work to be carried out without having almost any adverse effect on the cotton work. In addition, hot metal continuously settles to the bottom of the furnace during cotton milling, and in this state, the furnace body is tilted in the opposite direction to the cotton milling process and extracted, so the separation of the hot metal and raw materials is clear, and only the hot metal is removed. It is not necessary to discharge a large amount of raw material melt. Furthermore, since the raw material discharge port is located at a position sufficiently higher than the bottom of the furnace, it is possible to leave the hot metal until it has accumulated to a certain extent, and there is little interruption in the continuous cotton milling operation.
Since the tilting device for discharging raw materials is used in the opposite direction,
A separate drive device is not required for discharging hot metal. By establishing such a method for extracting hot metal, the present invention has made possible an extremely simple system in which raw materials can be directly supplied from a ladle car to a cotton machine via an electric furnace, and has been developed to improve industrial efficiency. The effect is great.

[Brief explanation of drawings]

The figure is a longitudinal sectional view of an electric furnace suitable for carrying out the method of the present invention. 1... Electric furnace main body (melting furnace), 9... Outlet,
10... Cotton machine, 18... Hot metal, 19... Hole punch, 20... Hole opening (tapping port).

Claims (1)

[Claims] 1. Charge molten slag into a melting furnace, adjust the composition, tilt the furnace while heating and maintaining it within a constant temperature range, and pour a substantially constant amount of slag from an outlet slightly above the bottom of the furnace. In the operation of an electric furnace that produces rock wool by discharging molten material, a hole can be made with a hole puncher on the side wall of the bottom of the furnace on the opposite side of the outlet from the center of the melting furnace. A tap hole is provided that is closed with a plugged mud, and a hole is opened with a hole puncher every time a certain amount of molten slag is processed, the hot metal accumulated at the bottom of the furnace is extracted, and then a mud is pushed into the opening and closed. A method for extracting hot metal from a rock wool raw material melt, characterized by the following. 2. The rock wool according to claim 1, wherein after the taphole is opened, the hot metal accumulated at the bottom of the furnace is removed by tilting the furnace body in a direction opposite to the outflow side to the cotton mill. Method for extracting hot metal from melted raw material.