JPH08200968A - Method and apparatus for preheating melting material - Google Patents

Abstract

PURPOSE: To prevent the abnormal combustion and to preheat a melting material at a high temperature by supplying oxygen to incompletely burnt gas exhausted from a melting furnace to completely burn the gas, and further heating the exhaust gas by the combustion heat to preheat the material. CONSTITUTION: When it occurs necessary to preheat steel scrap 30, a slide valve 22 is opened, and the scrap 30 is dropped in an inner tube 24 to be charged. On the other hand, carbon monoxide of high temperature exhausted from the opening 10b of a rotary burner furnace 10 is reacted with oxygen introduced from the gap to an exhaust tube duct 28 to become carbon dioxide. The adherend adhered to the scrap 30 is evaporated by the preheating, and recovered to a duct collector. The exhaust gas such as the carbon dioxide, etc., further becoming the high temperature by the chemical reaction is cooled while moving along between the tube 24 and the duct 28, moved in a direction of an arrow D6 via a dust collecting exhaust tube 26, and recovered to the collector. In this moving, the carbon dioxide is introduced into the meshlike tube 24, and the scrap 30 can be entirely preheated at the uniform temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for preheating a molten material, and more particularly to a technique for preheating the molten material before charging it into a melting furnace.

[0002]

2. Description of the Related Art Conventionally, melting materials (for example, steel scrap, pig iron, cast iron, iron alloys, etc.) are melted in a melting furnace (for example, cupola, electric furnace,
One of the techniques for preheating the melted material before introducing it into an induction furnace or the like) is disclosed in Japanese Examined Patent Publication No. 63-50406. In the technique of the publication, the melting material held above the melting furnace (molten metal) is preheated by radiant heat or convective heat generated from the melting furnace. The preheated melting material is dropped (input) into the melting furnace and melted. Therefore, according to this technique, the energy required to dissolve the melting material can be suppressed low.

On the other hand, the applicant has not yet published at the time of the application, but in order to prevent the oxidization of the melting material in the melting furnace,
We are developing a melting furnace that melts melting materials in a reducing atmosphere. In this melting furnace, incomplete combustion gas (for example, carbon monoxide) is generated during combustion in order to create the reducing atmosphere. That is, combustion is performed in a state where the ratio of combustion gas and oxygen is slightly reduced from the ideal ratio. Since this incomplete combustion gas is constantly generated by combustion, a part of the incomplete combustion gas is discharged from the melting furnace. Since the incomplete combustion gas discharged in this manner has a high temperature, it is cooled through the exhaust pipe duct and is discharged to the atmosphere as it is. In this case, the inside of the melting furnace is in an oxygen-deficient state, and the oxidation of the melting material is prevented.

[0004]

In the reducing atmosphere type melting furnace developed by the present applicant, the convective heat of the high temperature incomplete combustion gas generated by the combustion is utilized as in the prior art. If the molten material is preheated, the high temperature incomplete combustion gas irregularly reacts with the oxygen which flows backward through the exhaust pipe duct to cause abnormal combustion. In particular, when the melted material is loaded into the exhaust pipe duct, abnormal combustion is likely to occur because oxygen is entrained together with the melted material.
When such abnormal combustion occurs, the melted material is oxidized,
The melting materials will weld together. Then, when the oxidized melting material or the deposited melting material is melted in the melting furnace, a large amount of slag is generated, resulting in a problem that the melting efficiency is lowered. The present invention has been made in view of the above points, and an object thereof is to completely burn an incomplete combustion gas generated in a melting furnace to prevent abnormal combustion, and use the combustion heat for preheating a melting material. It is to be.

[0005]

A first aspect of the present invention is a preheating method for preheating a melting material before charging the melting material into a melting furnace, which is an incomplete high temperature exhausted from the melting furnace. The method includes a step of supplying oxygen to the combustion gas to complete combustion, and a step of preheating the melting material by further heating exhaust gas by the combustion heat generated by the complete combustion.

[0006]

According to the first aspect of the invention, the incomplete combustion gas discharged from the melting furnace is reacted with oxygen for complete combustion. The exhaust gas is further heated by the combustion heat generated during the complete combustion, and the molten material is preheated by the heated exhaust gas. Since the incomplete combustion gas discharged from the melting furnace is completely combusted, it becomes a chemically stable complete combustion gas. Therefore, the incomplete combustion gas does not come into direct contact with the melted material, so that abnormal combustion can be prevented.

[0007]

A second aspect of the present invention is a preheating device for preheating a melting material before charging it into a melting furnace, the preheating device being connected to the melting furnace. An exhaust pipe duct for inducing incomplete combustion gas discharged from the melting furnace, an oxygen supply means for supplying oxygen into the exhaust pipe duct, and an exhaust pipe duct provided in the exhaust pipe duct and discharged from the melting furnace. A reaction section for reacting the incomplete combustion gas with the oxygen supplied by the oxygen supply means, and a loading section for loading the melting material preheated by the exhaust gas further heated by the combustion heat generated by the reaction. It has a partition part.

[0008]

According to the second aspect of the present invention, the incomplete combustion gas discharged from the melting furnace reacts with the oxygen introduced by the oxygen supply means and is completely combusted in the reaction zone. Then, the exhaust gas is heated by the combustion heat generated by this complete combustion, and the molten material loaded in the loading section partitioned by the partition section is preheated by the heated exhaust gas. Therefore, the exhaust gas heated by the combustion heat is transferred to the pre-loaded melt material through the partition that separates the reaction section and the loading section,
Preheat the melt. Therefore, it is possible to efficiently preheat the melting material.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. In this example, a case where steel scrap is used as a melting material and carbon monoxide (CO) is used as an incomplete combustion gas will be described. First, FIG. 1 is a schematic diagram showing a preheating device for carrying out the present invention. In the figure, the preheating device is roughly divided into a rotary burner furnace 10, an exhaust pipe duct 28, and a material drop prevention device 40.

The rotary burner furnace 10 is one of melting furnaces for melting the steel scrap 30. The rotary burner furnace 10 has a cylindrical shape having conical portions at both ends (or one end), and is configured to be rotatable in the arrow 10 direction around the axis of the cylindrical shape. Also,
The rotary burner furnace 10 is attached to a pedestal 16 and is configured to be tiltable in the direction of arrow 11 about a tilting shaft 14 thereof. The power means for rotating and tilting the rotary burner furnace 10 includes, for example, a combination of an electric motor and a hydraulic (or air) cylinder.

Further, the opening 10a at one end of the rotary burner furnace 10 is a discharge port after melting the steel scrap 30,
A gas burner 12 is attached. On the other hand, the opening 10b at the other end of the rotary burner furnace 10 is an insertion port for inserting the steel scrap 30, and is also a guide port for guiding carbon monoxide generated during melting to the exhaust pipe duct 28.

Here, the inside of the rotary burner furnace 10 is kept in a reducing atmosphere in order to prevent oxidation of the steel scrap 30 before and after melting. This reducing atmosphere makes the combustion state of the gas burner 12 incomplete, facilitates the generation of carbon monoxide, and reduces the carbon dioxide (CO) to carbon dioxide (CO).
Ratio of ₂₎ (CO / CO ₂₎ is achieved by adjusting the 0.2 to 6. That is, the gas burner 12
When burning a combustion gas such as LPG (liquefied petroleum gas), the incomplete combustion is performed by slightly reducing the oxygen ratio from the theoretical combustion ratio of the combustion gas and oxygen. Makes it easy to generate carbon monoxide and creates a reducing atmosphere. Specifically, when the ratio of LPG and oxygen is 1: 5, the theoretical combustion state occurs, but LPG is 1
When 0 nm ³ / h, oxygen can be achieved incomplete combustion state of 45 Nm ³ / h Tosureba above.

Next, the exhaust pipe duct 28 is connected to the opening 10b at the other end of the rotary burner furnace 10 with a gap provided between the exhaust pipe duct 28 and the rotary burner furnace 10. This is a duct for guiding exhaust gas such as carbon to the dust collector through the dust collection exhaust pipe 26. The opening 10b
The gap between the exhaust pipe duct 28 and the exhaust pipe duct 28 specifically realizes the oxygen supply means. With this configuration, the opening 10b
Oxygen (O ₂ ) easily enters through the gap between the exhaust pipe duct 28 and the exhaust pipe duct 28. Therefore, the high temperature carbon monoxide discharged from the opening 10b reacts with the incoming oxygen as shown in the following equation. 2CO + O ₂ → 2CO _{2 By} this reaction, carbon monoxide is completely combusted to form carbon dioxide (complete combustion gas). Further, due to the reaction with oxygen, carbon dioxide is heated to a temperature higher than that of carbon monoxide.

Inside the exhaust pipe duct 28, an inner pipe 24 is provided apart from the inner wall of the exhaust pipe duct 28. That is, the exhaust pipe duct 28 and the inner pipe 24 are double pipes. Further, a dust collecting exhaust pipe 26 is connected to the exhaust pipe duct 28, and guides the exhaust gas and the like, which is discharged from the rotary burner furnace 10 and becomes carbon dioxide, to the dust collector.

Here, the inner pipe 24 is a device embodying a partition part, the inside thereof is a loading compartment for loading the steel scrap 30, and the outside thereof is a reaction compartment in which carbon monoxide reacts with oxygen. . The inner pipe 24 is made of a mesh-shaped heat-resistant steel plate, and is connected to the material hopper 20 provided at one end of the exhaust pipe duct 28. On the other hand, the inner pipe 24 on the other end side of the exhaust pipe duct 28 is provided with a door in order to prevent the steel scrap 30 from spilling. With this configuration, the steel scrap 30 temporarily stored in the material hopper 20 is stored.
Is dropped into the inner pipe 24 by opening and closing the slide valve 22 (in the direction of arrow 1) and is loaded for preheating. Also, the inner pipe 2
Since 4 is configured in a mesh shape, further heated carbon dioxide easily passes through the gap of the steel scrap 30 loaded. Therefore, the steel scrap 30 loaded in the central portion of the inner pipe 24 is also easily preheated, and the steel scrap 30 can be preheated at a uniform temperature throughout.

The exhaust pipe duct 28 near the rotary burner furnace 10 is provided with a charging device 34 for charging the preheated steel scrap 30 into the rotary burner furnace 10.
This charging device 34 is equipped with a charging cylinder 32, and the charging cylinder 32 is slid horizontally (direction of arrow D5) to charge the preheated steel scrap 30 into the rotary burner furnace 10. With this configuration, the preheated steel scrap 30 can be reliably charged into the rotary burner furnace 10 without remaining.

Next, the material drop prevention device 40 is a device for preventing the preheated steel scrap 30 from dropping when it is charged into the rotary burner furnace 10. That is, a gap is provided between the rotary burner furnace 10 and the exhaust pipe duct 28 for supplying oxygen into the exhaust pipe duct 28 as described above. In this state, even if the preheated steel scrap 30 is to be charged into the rotary burner furnace 10, it will fall from the gap. Therefore, when the steel scrap 30 is charged into the rotary burner furnace 10, the elevating cylinder 38 including the cover 36 having the radial shape of the inner pipe 24 is at least raised and brought into the state shown in FIG. After the steel scrap 30 is charged, for example, when the molten steel scrap 30 is discharged,
The elevating cylinder 38 is lowered to the state shown in FIG. In this way, by moving the elevating cylinder 38 up and down in the direction of arrow D4, all the steel scrap 30 can be reliably charged into the rotary burner furnace 10.

Next, steps for preheating the steel scrap 30 and charging it into the rotary burner furnace 10 will be described. First,
In FIG. 1, the steel scrap 30 (melting material) is the material hopper 20.
Will be temporarily stored in. Then, as after the steel scrap 30 is charged into the rotary burner furnace 10 (melting furnace), the steel scrap 3
When it becomes necessary to preheat 0, the slide valve 22 opens.
When the slide valve 22 is opened, the steel scrap 30 moves into the inner pipe 24.
Is dropped and loaded.

On the other hand, the opening 10 of the rotary burner furnace 10
High temperature carbon monoxide discharged from b (incomplete combustion gas)
Reacts with oxygen that has entered through the gap (oxygen supply means) from the exhaust pipe duct 28 to become carbon dioxide (complete combustion gas). [Process of Completely Combusting Incompletely Combusted Gas] This carbon dioxide is a chemically stable substance, and is heated to a high temperature by being further heated by the reaction with oxygen. Therefore, abnormal combustion such as explosion does not occur after the reaction. It should be noted that the deposit (such as zinc) attached to the steel scrap 30 is evaporated by the preheating. After this deposit evaporates,
It is collected by the dust collector through the exhaust pipe duct 28 and the dust collecting exhaust pipe 26.

Exhaust gas such as carbon dioxide which has become higher in temperature due to a chemical reaction or other gas (for example, nitrogen gas or nitrogen-based gas) discharged from the opening 10b of the rotary burner furnace 10 is supplied to the inner pipe 24. (Partition) and exhaust pipe duct 2
It moves along between 8 (reaction section), and is cooled with the movement. Then, through the dust collecting exhaust pipe 26, an arrow D
It moves in 6 directions and is finally collected by the dust collector. During the above-mentioned movement, carbon dioxide is used as the mesh-shaped inner tube 2
4 enters the inside (loading section) and passes through the gap of the steel scrap 30 loaded in the inner pipe 24. [Step of Preheating Melting Material by Combustion Heat] Therefore, not only the steel scrap 30 near the wall of the inner pipe 24 but also the steel scrap 30 loaded in the central portion of the inner pipe 24 is easily preheated, and the steel scrap is preheated. The 30 can be preheated at an overall and uniform temperature.

When the steel scrap 30 is preheated in this way, the lifting cylinder 38 having the cover 36 is lifted (state shown in FIG. 2). Then, the charging cylinder 32 of the charging device 34 is slid to charge the steel scrap 30 into the rotary burner furnace 10. After that, the lifting cylinder 38 is lowered (see FIG. 1).
State). In this way, all the preheated steel scrap 30 can be reliably charged into the rotary burner furnace 10.

The rotary burner furnace 10 of 250 kg is used.
In the test conducted in the (test furnace), that is, the result of heating the steel scrap 30 (150 Kg) for 36 minutes using oxygen (27.0 Nm ³ ) and LPG (6.0 Nm ³ ),
A reducing atmosphere consisting of about 30% carbon monoxide, about 20% carbon dioxide and the balance of water, hydrogen and a small amount of nitrogen could be realized in the rotary burner furnace 10. Further, due to this heating, the temperature inside the rotary burner furnace 10 is 404 ° C., and the upper part of the exhaust pipe duct 28 (the exhaust pipe 26 for collecting dust is the exhaust pipe duct 28).
The temperature in the vicinity of the point connected to () was 32 ° C.
From these results, by carrying out the present invention, the steel scrap 30 can be heated up to about 400 ° C. (or higher temperature).
It can be preheated and the oxidation of the steel scrap 30 can be prevented. The above test shows the result when the steel scrap 30 is maximally loaded into the inner pipe 24.
By adjusting the amount of 0
It is also possible to preheat to a high temperature up to 00 ° C.

Here, in the above-described embodiment, the oxygen supply means is realized by a structure in which a gap is provided between the opening 10b at the other end of the rotary burner furnace 10 and the exhaust pipe duct 28, which is shown in FIG. So that the opening 10b and the exhaust pipe duct 2
If it is not necessary to provide a gap between the fan 8 and
The oxygen supply means may be realized by connecting the blower pipe 42 extending from 4 to the rotary burner furnace 10 side. The blower 44 and the blower pipe 42 are an oxygen supply device described later. In this configuration, oxygen is supplied from the blower 44 to the exhaust pipe duct 28 through the blower pipe 42, so that the exhaust pipe duct 28 does not become deficient in oxygen, and one of the high temperatures reliably discharged from the rotary burner furnace 10 is maintained. The carbon oxide can be completely burned.

Here, it is possible to supply oxygen into the exhaust pipe duct 28 by simply making a hole in the exhaust pipe duct 28 close to the rotary burner furnace 10 side, not limited to the above configuration. Further, not only the blower 44, but also a device such as a compressor for forcibly supplying oxygen to the exhaust pipe duct 28 can be similarly applied.

Furthermore, a rotation control device for controlling the rotation speed of the blower 44 is provided, and an air flow amount detection device for detecting the air flow amount of carbon monoxide is provided in the exhaust pipe duct 28 near the rotary burner furnace 10 side. Then, the rotation control device causes the blower 44 to operate according to the air volume of the carbon monoxide detected by the air volume detection device.
Control the rotation speed of. With this configuration, it is possible to supply the optimum oxygen capacity for performing complete combustion. Further, since oxygen at the outside temperature (low temperature) is not excessively supplied into the exhaust pipe duct 28, the temperature inside the exhaust pipe duct 28 can be maintained high.

Although one embodiment of the method and apparatus for preheating the melted material has been described above, the structure, shape, size, material, number, arrangement and operating conditions of the other parts of the method and apparatus for preheating the melted material are described. Also, the present invention is not limited to this embodiment. For example, the inner pipe 24 is provided separately from the inner wall of the exhaust pipe duct 28, but the inner pipe 24 is provided spirally along the inner wall (or the outer wall) of the exhaust pipe duct 28, or the exhaust pipe duct is provided. It may be configured to be provided in a zigzag shape (or step shape) inside 28.

Alternatively, a partition (corresponding to the inner pipe 24) that divides the exhaust pipe duct 28 into two is provided, one of which is a reaction section where carbon monoxide and oxygen react, and the other is a melting material (steel scrap 30). It may be a loading compartment for loading. Similarly, a partition that divides the exhaust pipe duct 28 into three or more parts may be provided, and a predetermined number of compartments therein may be reaction compartments, and the remaining other compartments may be loading compartments. By taking the optimum configuration depending on the type of the melting material, it is possible to preheat the melting material more generally and uniformly.

Further, although the steel scrap 30 is applied as the melting material, the present invention can be applied to the melting material such as pig iron, cast iron, and iron alloy. Similarly, although carbon monoxide (CO) is applied as the incomplete combustion gas, other incomplete combustion gas that prevents the oxidation of the melted material before and after the melting may be applied. As described above, even when other melting material or incomplete combustion gas is applied, the same effect as that of the present invention can be obtained.

The embodiments of the present invention have been described above. However, in addition to the technical matters described in the scope of the claims, the embodiments of the present invention include various technical aspects as described below. Have. [Structure] The preheating device for melted material according to claim 2, further comprising an oxygen supply device which is provided so as to be connected to the exhaust pipe duct and forcibly supplies oxygen into the exhaust pipe duct.

[Operation of the above configuration] Oxygen is forcibly supplied into the exhaust pipe duct by the oxygen supply device.

[Effects of the above configuration] Since oxygen deficiency is prevented, incomplete combustion gas discharged from the melting furnace can always be completely combusted.

[0032]

As described above, according to the first aspect of the invention, the incomplete combustion gas discharged from the melting furnace is reacted with oxygen to completely burn it, and the melting heat is generated by the combustion heat generated during the complete combustion. Since the preheating is performed, the incomplete combustion gas discharged from the melting furnace is completely combusted and becomes a chemically stable complete combustion gas. Therefore, the incomplete combustion gas does not come into direct contact with the melted material, and abnormal combustion can be prevented. Further, since the complete combustion gas becomes even hotter due to the complete combustion, it is possible to preheat the melting material to a higher temperature.

Further, in the second aspect of the present invention, the incomplete combustion gas discharged from the melting furnace in the reaction section reacts with oxygen taken in by the oxygen supply means, and the exhaust gas is generated by the combustion heat generated by the complete combustion. Since it is configured to heat and preheat the melted material loaded in the loading section partitioned by the partition section by the heated exhaust gas,
The exhaust gas heated by the heat of combustion is transmitted to the pre-dissolved material through the partition that separates the reaction section and the loading section. Therefore, the melting material can be preheated entirely and uniformly.

[Brief description of drawings]

FIG. 1 is a schematic view showing a preheating device for carrying out the present invention.

FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1 and is a schematic diagram showing the configuration of the material drop prevention device.

FIG. 3 shows a partially enlarged view of FIG.

FIG. 4 is a schematic diagram showing another configuration of the oxygen supply means.

[Explanation of symbols]

 10 Rotary Burner Furnace (Smelting Furnace) 12 Gas Burner 20 Material Hopper 24 Inner Tube (Partitioning Section) 26 Dust Collection Exhaust Pipe 28 Exhaust Pipe Duct 30 Steel Scrap (Dissolving Material) 32 Charging Cylinder 34 Charging Device 36 Cover 38 Elevating Cylinder 40 Material Fall Prevention Device 42 Air Supply Pipe 44 Blower (Oxygen Supply Means)

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[Procedure amendment]

[Submission date] January 27, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

The rotary burner furnace 10 is one of melting furnaces for melting the steel scrap 30. The rotary burner furnace 10 has a cylindrical shape having conical portions at both ends (or one end), and is configured to be rotatable in the arrow D 10 direction around the axis of the cylindrical shape. Further, the rotary burner furnace 10 is attached to a pedestal 16 and is configured to be tiltable in a direction of an arrow D 11 about a tilt shaft 14 thereof. The power means for rotating and tilting the rotary burner furnace 10 includes, for example, a combination of an electric motor and a hydraulic (or air) cylinder.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

Here, the inner pipe 24 is a device embodying a partition part, the inside thereof is a loading compartment for loading the steel scrap 30, and the outside thereof is a reaction compartment in which carbon monoxide reacts with oxygen. . The inner pipe 24 is made of a mesh-shaped heat-resistant steel plate, and is connected to the material hopper 20 provided at one end of the exhaust pipe duct 28. On the other hand, the inner pipe 24 on the other end side of the exhaust pipe duct 28 is provided with a door in order to prevent the steel scrap 30 from spilling. With this configuration, the steel scrap 30 temporarily stored in the material hopper 20 is stored.
Is dropped into the inner pipe 24 by opening and closing the slide valve 22 (direction of arrow D 1) and is loaded for preheating. Further, since the inner pipe 24 is formed in a mesh shape, the carbon dioxide that has been heated further easily passes through the gap of the steel scrap 30 that is loaded. Therefore, the steel scrap 30 loaded in the central portion of the inner pipe 24 is also easily preheated, and the steel scrap 30 can be preheated at a uniform temperature throughout.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (71) Applicant 591181089 Naniwa Reactor Research Institute Co., Ltd. 8-1-5-1, Ageo-cho, Yao-shi, Osaka Prefecture (72) Inventor Yuji Okada 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Vehicle Co., Ltd. (72) Inventor Hirokazu Shirakawa 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd. (72) Inventor Harumi Hirano 2-chome, Toyota-cho, Kariya-shi, Aichi Stock Corporation Toyota Industries Corporation (72) Inventor Yuji Kamiya, 2-chome, Toyota-cho, Kariya city, Aichi Prefecture Toyota Industries Corporation (72) Inventor, Hiroshi Kobayashi 2-chome, Toyota-machi, Kariya city, Aichi Corporation Toyota Industries Corporation (72) Inventor Hiroyuki Tsuruoka 1-9-1, Shinonome, Koto-ku, Tokyo Teisan Co., Ltd. Head Office Branch Office (72) Inventor Takaba 4-8 Masaki, Naka-ku, Nagoya-shi, Aichi Tesan Co., Ltd., Chubu Office (72) Inventor Hiroyuki Tanaka 4--8, Masaki, Naka-ku, Nagoya-shi, Aichi Teisan Co., Ltd. Chubu Office (72) Inventor Hirotoshi Murata Eight-share company, Naniwa Reactor Research Laboratory, 5-1, Ageo-cho, Yao-shi, Osaka

Claims (2)

[Claims] 1. A preheating method for preheating a molten material before charging it into a melting furnace, comprising the steps of supplying oxygen to a high temperature incomplete combustion gas discharged from the melting furnace to complete combustion, and a complete combustion thereof. And a step of preheating the melting material by further heating the exhaust gas by the combustion heat generated in 1., the preheating method of the melting material. 2. A preheating device for preheating a melting material before charging it into a melting furnace, the exhaust pipe duct being connected to the melting furnace and guiding an incomplete combustion gas discharged from the melting furnace. An oxygen supply means for supplying oxygen into the exhaust pipe duct, and an incomplete combustion gas discharged from the melting furnace, which is provided in the exhaust pipe duct, to react oxygen supplied by the oxygen supply means. And a partitioning section for partitioning a reaction section for allowing the melted material, which is preheated by the exhaust gas further heated by the combustion heat generated by the reaction, into a loading section, and a preheating device for the melted material. .