JPH07332866A - Gyratory melting furnace - Google Patents

Abstract

PURPOSE:To extend the range to which the effect of a flame reaches so as to accelerate the fusion in speed by inducing gyratory motion in the melt in a furnace body with a burner for gaseous or liquid fuel placed at the top of the furnace lid at an angle of injection by 5-30 degrees to the perpendicular line of the furnace body. CONSTITUTION:Eccentric motion is produced with respect to the central, vertical axis of a furnace body of the shape of a crucible or bowl. A gyratory melting furnace of new type, enabling melting of metal in a sound way with advantages in the control of the components and metallurgical aging of the melt, is obtainable by equipping the furnace with a gyratory device for giving agitating energy of gyratory notion to the melt in a crucible- or bowl-shaped furnace in the aforementioned manner and with a burner 5 in the upper part of the furnace lid 4 at an angle of injection of 5-15 degrees in the case of a crucible-shaped furnace body 1 and at an angle of injection of 5-30 degrees in the case of a bowl-shaped furnace body 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention supplies a heat source to a crucible-shaped or mortar-shaped furnace body at an entrance angle of 5 to 30 degrees in melting and refining a metal, and also allows the furnace body to undergo a gyration motion (corrugation). The present invention relates to a gyratory melting furnace that uses a gas or liquid fuel to newly supply a metallurgical reaction and rapid melting by supplying heat for melting to a metal while performing exercise.

[0002]

2. Description of the Related Art Conventionally, there have been the following melting furnaces for melting and refining metals, but these have inherent problems to be improved. That is, 1. Electromagnetic induction melting furnace The induction melting furnace with low frequency and high frequency is widely used as a typical crucible melting furnace of this furnace, and thermal efficiency is low due to heat loss due to water cooling of coil accompanying heating. This is a well-known fact. Further, it is not known to utilize the heat of the exhaust gas from the top of the induction melting furnace for melting.

2. Crucible-shaped and U-shaped melting furnaces Some crucible-shaped and U-shaped melting furnaces directly or indirectly introduce the heat of fuel combustion from the top or side of the furnace. Typically, it is used for melting copper alloys and light alloys. Further, for the melting of the iron alloy, melting was attempted by a gas burner using pure oxygen inserted vertically into the crucible from the crucible top, but since the burner is hung vertically from the furnace top center, the life of the burner, Due to problems such as flame stability, it has not been put to practical use.

3. Arc light type electric melting furnace A typical example of the bowl-shaped melting furnace is the Eru type arc electric melting furnace. Electric power is used for the heat source, power efficiency,
It seems that there still remain major problems such as thermal efficiency, noise, and dust.

[0005]

The problem to be solved by the present invention is to inherit the advantages of the crucible-type induction melting furnace such as compactness, manoeuvrability, selectivity of the melting raw material, and stability of the material as they are. , A clean, economical and metallurgical crucible-shaped or mortar-shaped high-temperature melting furnace in which electric power is replaced by gas or liquid fuel.

Therefore, in order to supply high-temperature combustion gas at the same time as the V-shaped crossing with the metal charged in the crucible-shaped or mortar-shaped furnace body, the furnace lid and the vertical axis of the furnace body are supplied at the same time. On the other hand, a burner is arranged at an entrance angle of 5 to 30 degrees to operate integrally with the furnace body, and the combustion heat of the fuel due to the oxygen-rich mixed air or oxygen is directly supplied to the metal and the radiant heat of the molten metal is used to burn the burner. Pre-heating of the charging metal to improve the melting heat efficiency, supplementing the molten metal to the molten metal to improve the melting of the added metal into the molten metal, and stirring by gyratory motion to efficiently melt the additional alloying elements It is to enable the temperature of the molten metal to rise and the metallurgical reaction.

In particular, in recent years, there has been a growing interest in electric power costs for metal melting, their supply and demand, and a clean environment.
Since the advent of a melting furnace with improved quality, economical efficiency and workability is strongly demanded, the present invention was created in accordance with these requirements, and an oxygen-rich mixed air is used for combustion of fuel in an operation furnace. A new gyratory melting furnace that uses oxygen or oxygen, preheats the metal and reducing agent, and agitates the molten metal by gyratory motion to further adjust the components and further enhance the metallurgical aging of the molten metal to achieve sound metal melting The purpose is to provide.

[0008]

In order to achieve such an object, the present invention provides an inside of a crucible-shaped or mortar-shaped furnace by eccentrically rotating with respect to a central vertical axis of a crucible-shaped or mortar-shaped furnace body. Apparatus for applying stirring energy of gyratory motion to the molten metal, and a burner for combustion arranged on the top furnace lid of the crucible-shaped or mortar-shaped furnace body at an entry angle of 5 to 30 degrees with respect to the normal to the furnace body And a gyrate melting furnace for preheating the flue gas through the preheating device for the bullion on the outside of the furnace body.

[0009]

The point of emphasis in the present invention is to use mixed air for combustion of fuel, and combustion with pure oxygen may be used if only high temperature combustion is expected. In a mixed atmosphere, the atmosphere containing nitrogen (N ₂ ) and argon (Ar) gas oxidizes to dissolved metal more than the pure strong oxidizing atmosphere of high temperature CO ₂ + H ₂ O by burning with pure oxygen in I know that the reaction is mild.

In the second, a reducing material, that is, a small-sized or medium-sized carbonaceous agglomerate is mixed and charged together with a charging metal, and a gas atmosphere containing CO or CH 2 is added to the atmosphere during heating and melting. In addition, it is possible to obtain a molten metal whose composition adjustment and metallurgical aging have been completed by adding alloying elements and carbonaceous substances as a finish of the molten metal and stirring the molten metal by a gyratory device at the same time. It is what

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A basic embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a crucible-shaped gyratory melting furnace according to the present invention, and FIG. 2 shows a mortar-shaped gyratory melting according to the present invention. FIG. 1 is a schematic vertical sectional view showing an example of a melting furnace, and is a crucible-shaped furnace body 1 or a mortar-shaped furnace body 1 in FIGS. 1 and 2.
Is suspended and fixed to the gyratory device 8 along the vertical axis of the furnace body. The crucible furnace body 1 has an entrance angle of 5 to 15 degrees, and the mortar-shaped furnace body 1 has an entrance angle of 5 to 30 degrees. A combustion burner 5 is arranged above the lid 4.

Further, the burner 5 has 30% oxygen for combustion.
A 70% to 70% mixed air supply pipe or oxygen supply pipe 7 and a gas or liquid fuel supply pipe 6 are connected. The furnace body 1 and the combustion gas discharge part in the upper part of the furnace body are constructed of refractory materials 2, and the melting chamber 3 inside the furnace body 1 is provided with a tap hole 12 and a combustion exhaust gas discharge port 11. During melting and heating, the furnace top is closed by the furnace lid 4, the combustion burner 5 is integrated with the furnace lid 4, and the furnace lid 4 is provided with the furnace lid swiveling device 23 for opening and closing the furnace top. ing.

The flue gas enters the feeding basket 16 through the flue gas collecting stand 15 provided on the side of the furnace body and the flue gas inlet 18 at the bottom of the feeding bucket, preheats the metal and the reducing material 19, and then the flue gas duct hood. 21 and duct 22
Forcibly discharge to the dust collector. Further, in order to discharge the molten metal, an elevating device 9 for raising the melting furnace body and a tilting device 10 for discharging the molten metal are installed.
The gyratory melting furnace is configured so that the molten metal is discharged from the tap hole 12 by tilting the furnace body 1.

The metallurgical melting and refining process of the present invention having the above-described structure will now be described with reference to FIGS. 3 and 4. FIG. 3 shows the state of the metal 26 and the carbon material 27, the burner flame 28 with a slant angle, etc., which was charged into the furnace after being preheated. The metal 26 reacts with the heat of combustion of fuel and carbon dioxide (CO ₂ ) and steam (H ₂ O) of the gas produced by combustion with the input carbon material (C), that is, CO ₂ + C → 2C.
After being melted down in an atmosphere containing a reducing gas component such as O, H ₂ O + C → CO + 2H to 2CH ₂ + CO ₂ , the temperature rise is advanced.

Carbon materials, ferroalloys, etc. are added to adjust the components as the temperature of the melt rises, and the energy of the gyratory motion is applied to the melting furnace to continue the gentle centrifugal stirring and heating of the molten metal for metallurgical refining. The process of obtaining a healthy molten metal is shown in FIG. The molten metal during the gyratory motion shown in FIG. 4 rises 29 by centrifugal force along the furnace wall, and the burner flame 28 is in a state 30 in which it is in large contact with the molten metal surface. After the temperature is raised, the components are adjusted, and the molten metal is aged, the molten metal is discharged from the discharge port 12.

Since the gyratory melting furnace has been described in the above embodiment, the actual operation result will be explained as a second embodiment. In this operation, about the input metal, pig iron; 3
0% (90 kg), old pig; 30% (90 kg), steel scrap;
40% (120 kg), coke; 4%, Fe-Si;
2%, limestone; dissolved at 3%. The procedure for charging into the furnace is as shown in Fig. 5, which shows the optimum method. The operating conditions are as follows: gas consumption LPG; 43.6 kg (50 kg /
h), oxygen charge; 90 m ³ (102 m ³ / h), LPG gas pressure; 0.22-0.41 Kg / cm ² , oxygen pressure;
3.2 to 5.0 Kg / cm ² , cooling water temperature; 25 to 42
C, gas temperature; 46-78 C, furnace wall temperature; 23-145
It was ℃.

The operation results are shown in FIG. 6 and Table 1. According to this, the temperature rises to 1300 ° C. in 23 minutes after the burner ignition and reaches 1530 ° C. in 51 minutes.
-Si 1% was put into the furnace, and was stirred for 6 minutes by the centrifugal force stirring by the gyration motion, and then tapped. The resulting changes in the components during the dissolution process are
The carbon (C) component showed a slightly decreasing tendency, and the silicon (Si) component had a wear loss of about 15%. Manganese and phosphorus did not seem to change much, indicating that sulfur (S) tends to absorb some from the coke.

[0018]

As Example 3, pig iron: 100%
(300 kg) (4.08% C, 2.35% Si, 0.
57% Mn, 0.067% P, 0.026% S), limestone; 3% (9 kg), Fe-Si; 1% (3 kg) based on the basic composition of the tensile strength in the melting process The experimental result for is illustrated. Operating conditions are LPG gas;
52.6 kg, oxygen; 107.6 m ³ , LPG gas pressure; 0.1 to 0.7 Kg / cm ² , oxygen pressure; 0.9 to
The temperature was 5.0 Kg / cm ² , the cooling water temperature was 20 to 55 ° C., and the gas temperature was 20 to 65 ° C. As shown in Table 2 of the experimental results of "melting condition and tensile strength", the tendency of the tensile strength became the strength following the elapsed melting time, showing a relatively uniform increasing tendency of the strength.

[0020]

【The invention's effect】

As described above, according to the present invention, the combustion burner is installed according to the present invention so that the entering angle is 5 to 30 degrees in the furnace lid with respect to the vertical axis of the furnace body. By arranging them integrally, heat exchange due to the intersection of the combustion gas and the input metal can be facilitated, the rebound of the flame to the burner can be mitigated, and the range of influence of the flame can be expanded by the gyrational motion. Dissolution rate is accelerated.

By using mixed air or oxygen enriched with oxygen for gently accelerating the combustion of fuel, and preheating the metal and introducing carbonaceous substances into the metal, the atmosphere during heating and melting can be positively affected. It is a high-temperature melting furnace that can increase the selection range of metal, that is, the type and size of pig iron and steel scrap, the amount and type of return material, etc. Instead, a molten metal melt having a high degree of maturity is obtained by stirring with a centrifugal force by the gyratory motion of the melt. By applying a gyratory motion to the crucible-shaped or mortar-shaped melting furnace main body in this way, it is a industrial furnace that achieves metallurgical high temperature melting and is clean, highly economical, and extremely useful in industrial production.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of a crucible-shaped gyratory melting furnace.

FIG. 2 is a schematic vertical sectional view of a mortar-shaped gyratory melting furnace.

FIG. 3 is a furnace state diagram at the time of charging of metal etc. into a crucible-shaped gyratory melting furnace.

FIG. 4 is a motion pattern diagram of molten metal during gyratory motion in the above.

FIG. 5 is a diagram showing how to inject metal into the furnace.

FIG. 6 is an operation record example showing the relationship between the elapsed time after burner ignition and the melting temperature.

[Explanation of symbols]

 1 melting furnace main body 2 refractory material lining 3 crucible-shaped or mortar-shaped melting chamber 4 swivel furnace lid 5 burner with burner lid 6 fuel supply pipe 7 oxygen or oxygen-enriched air supply pipe 8 gyratory device 9 furnace body Lifting device 10 Furnace body tilting device 11 Fuel exhaust gas outlet 12 Hot water outlet 13 Furnace body separating baffle plate 14 Clearance during furnace body gyration 15 Fuel exhaust gas collecting platform 16 Preheating and charging basket of input metal 17 Basket lifter 18 Exhaust gas introduction port to basket 19 Basket metal 21 Exhaust gas / duct hood 22 Forced exhaust gas pipe 23 Furnace lid swivel device 25 Refractory on exhaust gas exhaust lid 26 Metal bullion thrown into furnace body 27 Carbon substance thrown into furnace body 28 Burner Flame 29 Molten metal rising to furnace wall 30 Flame surface on the molten metal surface

Claims (3)

[Claims] 1. A crucible-shaped or mortar-shaped furnace body eccentrically moves with respect to a vertical axis to cause a gyrational motion (wave-shaped motion) in the molten metal in the furnace body. A gyratory melting furnace characterized in that a burner for burning a gaseous or liquid fuel is arranged at an entrance angle of 5 to 30 degrees with respect to the vertical line of the furnace body. 2. A crucible-shaped or mortar-shaped gyrate characterized by using mixed air or oxygen with an oxygen concentration of 30% or more as a gas or liquid fuel in order to achieve high-temperature metallurgical melting by metal melting. Lee melting furnace. 3. Preheating the metal in such a manner that exhaust gas burned in a crucible-shaped or mortar-shaped gyratory melting furnace is forcibly discharged from the top side of the furnace body through a metal charging basket. Gyratory melting furnace.