JPH1150118A - Smelting reduction equipment and its operation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the unit requirements of carbonaceous material and oxygen by fixing molten metal temp. in a furnace body to low even in the case of raising the molten metal temp. discharged from the furnace designated from the lower process to reduce the sensible heat of slag and the heat quantity of combustible gas and the extracted heat quantity from a water-cooling panel. SOLUTION: In an equipment for directly producing a molten metal 7, metal raw material, carbonaceous material and slag-making agent are added and pure oxygen and/or oxygen enriched gas are blown into the furnace body, and then, the molten metal 7 is stored in the bottom part of the furnace body, and the slag having sp. gr. smaller tan the molten metal is stored above the molten metal, and the molten metal and the molten slag are continuously or intermittently discharged from an iron tapping hole 1 through a molten metal pool part 9 to a molten iron ladle through a molten iron rough, and from a slag tapping hole 12 to a slag pan through a slag trough, respectively. In such a case, a duct 22 for recovering the combustible gas generated in the furnace body 1 is arranged, and also, burners are arranged in the molten metal pool part 9 and/or the molten iron trough and/or the molten iron ladle and a gas piping 24 divided from the duct is connected with the burners.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a smelting reduction apparatus for directly producing a molten metal by adding a metal raw material, a carbon material, and a slag-making material to a furnace body, and blowing pure oxygen and / or an oxygen-enriched gas. About.

[0002]

2. Description of the Related Art In smelting reduction, a metal raw material, a carbon material, and a slag-making material are added into a furnace body, and pure oxygen and / or an oxygen-enriched gas are blown into the slag to remove metal oxide in an iron raw material. This is a method for directly producing molten metal by reduction. In this method, a high-temperature combustible gas of about 1500 to 1700 ° C. is generated from the smelting reduction furnace.

[0003] This smelting reduction method, compared with the conventional blast furnace method,
Due to the high flexibility of production volume, that is, easy change of production volume, easy stop and restart of equipment, and small capital investment, it has recently been receiving attention especially as a small-scale molten metal production method. is there.

Generally, in this type of smelting reduction method, a preliminarily reduced metal raw material, a carbon material, and a slag-making material are added into a furnace body, and CO gas and H ₂ gas in a combustible gas generated from the furnace body are used. Two-stage method for preliminarily reducing metal raw materials (for example,
20607, JP-A-61-96019, etc.) and a metal material for reduction, a carbon material, and a slag material are added to the furnace body to reduce the metal oxide in the metal material in the slag. , CO gas in the combustible gas generated from the furnace body, H ₂
Gas is completely combusted in a waste heat boiler, the sensible heat of the combustion gases, recovered latent heat vaporized and for power generation or the like, or CO gas in the combustion gas and collected at the end of the combustion state H ₂ gas One-stage method used for other applications (for example,
No. 6, JP-A-61-279608, JP-A-62-179608
0-9815).

[0005] The two-stage method has the advantage of higher energy efficiency than the one-stage method, but requires a pre-reduction furnace such as a packed bed system or a fluidized bed system, so that the equipment is complicated and the capital investment is high. Defects such as the limitation of the shape of the iron raw material due to the uniformity of the reaction in the pre-reduction furnace (for example, only a bulk iron raw material can be used in a packed bed system and only a powdered iron raw material can be used in a fluidized bed system) There is a simple one recently
The column method is attracting attention.

In this one-stage method, the rate at which CO gas and H ₂ gas generated in the slag are burned in the furnace space above the slag (hereinafter referred to as the upper space) (hereinafter, the secondary combustion rate in the furnace). Nominal furnace internal combustion rate = (CO ₂ % + H ₂ O
%) / (Defined as CO ₂ % + CO% + H ₂ O% + H ₂ %) and effectively transferring the combustion heat to the slag, thereby improving energy efficiency, that is, reducing the carbon unit consumption. It is widely known that this can be done.

However, if the slag is not sufficiently stirred in the vertical direction, the heat transfer to the lower layer of the slag is reduced, only the upper layer of the slag is heated, the temperature difference between the upper space and the upper layer of the slag is reduced, and the temperature of the upper space is reduced. There is a problem in that the amount of heat transferred to the slag is reduced, and as a result, even if the secondary combustion rate is increased, the reduction in the carbon unit consumption is reduced. In this case, since the amount of heat transfer from the upper space to the slag decreases, the ambient temperature of the upper space increases, and when the refractory is lined with the furnace wall of the upper space, the amount of wear of the refractory increases rapidly. There was a problem.

Therefore, in order to solve these problems,
Equipped with a bottom blowing tuyere and an oxygen top blowing lance, put molten metal in a melting furnace lined with refractories on the furnace wall, control the amount of gas blown from the bottom blowing tuyere, and limit the slag composition and the amount of free carbon material Japanese Patent Application Laid-Open No. 60-9815 proposes a method of performing smelting reduction.

However, in this method, it is necessary to reduce the metal raw material and to vigorously agitate the slag in order to secure the amount of heat transfer from the upper space to the slag. There was a major difficulty in the refining operation in transmitting to the slag. That is, since the amount of the molten metal stirring gas is extremely large, there is a dilemma in that the non-oxygen gas causes a decrease in the temperature of the molten metal, while the inclusion of oxygen for maintaining the temperature causes the oxidation of the molten metal.

Therefore, in order to solve these problems,
A tuyere that blows an inert gas to agitate the metal under the metal bath, and a tuyere that blows oxygen or an oxygen-enriched gas into the slag, which is located above the metal bath and below the slag. Japanese Patent Application Laid-Open No. 61-279608 proposes a method using a smelting reduction furnace having a furnace wall and a refractory lined with a blowing lance.

However, even in this method, there is a problem to be described below because an inert gas is blown from a tuyere below a metal bath surface to stir the metal. The inert gas blown from the tuyere below the metal bath causes molten metal particles to be blown up into the slag, and the oxygen or oxygen rich gas blown into the slag from the tuyere located above the metal bath and below the slag. It is re-oxidized by the oxidizing gas and hinders the reduction rate, that is, the production rate. Due to the inert gas blown from the tuyere below the metal bath, the molten metal particles are blown up into the slag and suspended in the slag, so the heat capacity and thermal conductivity of the slag increase, and the furnace wall in contact with the slag increases. Since a water-cooled structure cannot be used and a refractory structure must be used, the refractory is greatly worn by slag and must be repaired or replaced frequently.

Since the heat capacity and the thermal conductivity of the slag increase, the tuyere located on the metal bath surface and on the slag surface cannot be water-cooled, and must be replaced by a consumable tuyere. There is a need to. The tuyere below the metal bath cannot be water-cooled due to the large heat capacity and thermal conductivity of the molten metal, and must be replaced by a consumable tuyere. The refractory around the tuyere below the metal bath is heavily worn and needs to be repaired or replaced frequently.

Therefore, in order to solve these problems,
Pure oxygen and / or oxygen-enriched gas is blown into the slag through the lower tuyere directed to the slag through the furnace body in the horizontal direction, and is passed through the upper tuyere directed through the furnace body to the upper space. A structure in which pure oxygen and / or oxygen-enriched gas is blown into a space and a water-cooled panel is lined in a region facing the upper space and the slag on the inner surface of the furnace body is disclosed in Japanese Patent Application Laid-Open No. 1-50.
No. 2276 has proposed this.

The prior art proposed in Japanese Patent Application Laid-Open No. 1-502276 will be described below with reference to a vertical sectional view of the furnace structure shown in FIG. The furnace main body 1 is fixed to a foundation 2, a water cooling panel 3 and a refractory 4 are lined on the inner surface of the furnace main body, and a raw material for adding an iron raw material, a carbonaceous material, and a slag-making material is placed on the upper part of the furnace main body 1. A port 5 and a gas discharge port 6 for discharging combustible gas generated from the furnace body are provided. Molten metal 7 is accumulated at the bottom of the furnace body 1, and foaming slag 8 having a lower specific gravity than the molten metal 7 is accumulated at the upper portion thereof. The molten metal 7 is supplied from the tap hole 11 through the molten metal reservoir 9, The waste is discharged continuously or intermittently from the slag port 12 through the slag reservoir 10.

The iron oxide (FeO and Fe ₂ O ₃ ) in the iron raw material input from the raw material input port 5
Is reduced in the foamed slag 8 by the reaction represented by the following formulas (1) and (2). FeO + C → Fe + CO (endothermic reaction) (1) Fe ₂ O ₃ + 3C → 2Fe + 3CO (endothermic reaction) (2)

Further, a part of the carbon content in the carbonaceous material supplied from the raw material working population 5 penetrates through the furnace body 1 and passes through the lower tuyere 13 provided toward the foamed slag 8.
It is oxidized by the reaction shown in the following formula (3) with the oxygen blown into it. C + 1 / 2O ₂ → CO (exothermic reaction) (3) The energy efficiency of this smelting reduction furnace, that is, the basic unit of carbon material is:
It is determined by the total carbon content required for the reactions of the equations (1), (2) and (3).

According to the above formulas (1), (2), and (3), the CO gas generated in the foamed slag 8 causes convection of the bubble in the foamed slag 8, so that the gas flows upward from the lower tuyere 13 in the furnace body. The specific gravity of the foamed slag 8 located is 1/2 to 1/3 of the specific gravity of the calming slag 16 in the slag reservoir 10, and it has been confirmed by the inventors of the test operation and the like.

Further, the CO gas and the hydrogen content in the carbonaceous material generated in the foamed slag 8 according to the above formulas (1), (2) and (3) are directed toward the upper space 15 above the bath surface of the foamed slag 8. Oxygen blown into the upper space 15 through the upper tuyere 14 disposed through the furnace body 1 and the foamed slag 8
In the upper space 15 above the bath surface of the following equation (4),
The oxidation reaction shown in (5) is performed. CO + 1 / 2O ₂ → CO ₂ (exothermic reaction) (4) H ₂ + 1 / 2O ₂ → H ₂ O (exothermic reaction) (5)

The reactions of the equations (4) and (5) are referred to as in-furnace secondary combustion, and the degree of the degree of the secondary combustion is represented by the in-furnace secondary combustion rate defined by the following equation (6). It is widely known that the secondary combustion rate is increased by increasing the flow rate of oxygen blown into the upper space 15 through the upper tuyere 14. Furnace secondary combustion rate = (CO ₂ % + H ₂ O%) / (CO ₂ % + CO% + H ₂ O% + H ₂ %) (6) where CO ₂ % and CO in the equation (6) _{%, H 2 O%, H} 2
% Indicates the volume fraction of each component of the combustible gas at the gas outlet 6.

When the secondary combustion rate in the furnace is increased, a part of the reaction heat of the equations (4) and (5) in the upper space 15 is transmitted from the upper space 15 to the foamed slag 8, and the equation ( By reducing the amount of carbon necessary for the exothermic reaction of 3), the carbon unit consumption is reduced. In this structure, all of the above-mentioned problems (1) to (5) have been solved because there is no tuyere below the surface of the metal bath into which an inert gas is blown for stirring the metal.

[0021]

However, this kind of furnace body structure still has the following problems. In the smelting reduction facility, the temperature of the molten metal discharged from the taphole is specified due to the restrictions of the down stroke, so when the specified temperature is high, the temperature of the slag must be increased by that much,
The temperature of the combustible gas discharged from the furnace body increases accordingly.

Therefore, when the temperature of the molten metal discharged from the taphole specified from the down stroke rises, for example, by about 100 ° C., the temperatures of the slag and the combustible gas discharged from the furnace body rise by about 100 ° C. In addition, the energy required for the operation is extra, and the amount of carbonaceous material and the specific unit of oxygen increase accordingly.

Further, as described above, when the temperature of the slag and the combustible gas discharged from the furnace body rises by about 100 ° C., when the water-cooled panel is lined in a range facing the upper space of the furnace body inner surface, Since the heat removal of the carbonaceous material increases, the carbonaceous material and the oxygen consumption rate further increase. this is,
In the water-cooled panel facing the upper space, for heat transfer to the water cooled panels is radiation heat transfer is mainly (the temperature of the combustion gas) ⁴ - approximately proportional to ⁴ (the surface temperature of the water-cooled panel), the slag This is because, in the faced water-cooled panel, heat transfer to the water-cooled panel is substantially proportional to (slag temperature)-(surface temperature of the water-cooled panel) because convective heat transfer is mainly performed.

Further, the refractory lining the furnace body has a high wear rate at a portion where the interface between the molten metal and the slag contacts, and a small wear rate at a portion where only the molten metal contacts.
As an example of the refractory lining the furnace body, FIG. 4 shows the results of measuring the wear rate of the interface between the molten metal and the slag of the alumina brick by changing the molten metal temperature. The temperature of the molten metal and the slag in the furnace main body is, for example, from 1400 ° C to 150 ° C.
When the temperature rises to 0 ° C. by 100 ° C., the refractory wear rate increases more than three times.

Further, in a slag composition of CaO / SiO ₂ = 1, molten metal temperature and phosphorus distribution ((P ₂ O ₅ ) /
FIG. 5 shows the relationship [P] ² ). Here, (P ₂ O ₅ )
Indicates the phosphoric acid concentration in the slag, and [P] indicates the phosphorus concentration in the molten metal. When the temperature of the molten metal in the furnace body is increased, as shown in FIG. 5, the phosphorus distribution ratio between the slag and the molten metal ((P
₂ O ₅ ) / [P] ² ) is reduced and the phosphorus concentration of the molten metal is increased.

The present invention has been made in order to solve the above-mentioned problems.
Even if the temperature of the molten metal discharged from the tap hole specified in the lower process rises, the sensible heat amount of the slag, the calorific value of the combustible gas, and the It is an object of the present invention to provide a smelting reduction facility that makes it possible to reduce the amount of carbonaceous material and oxygen consumption by reducing the amount of heat removed from a water-cooled panel.

[0027]

In order to solve the above-mentioned problems, the present invention adds a metal raw material, a carbon material, and a slag-making material to a furnace body and blows pure oxygen and / or an oxygen-enriched gas. At the bottom of the furnace body, molten metal accumulates, and at the top, slag with a lower specific gravity than the molten metal accumulates.Molten metal flows from the tap hole through the molten metal reservoir, and slag continues from the slag port. Or, in a facility for directly producing molten metal that is intermittently discharged, a duct for recovering combustible gas generated in the furnace body is provided, and a burner is provided on the ceiling or side surface of the molten metal reservoir, and the branch is branched from the duct. It is a smelting reduction facility characterized in that a gas pipe is connected to the burner, and the present invention also provides a molten metal through a molten metal reservoir through a molten metal reservoir to a molten metal ladle to a molten metal ladle, and a slag to a molten metal ladle. Or Through a slag gutter, to a slag pan, in a facility for directly producing molten metal that is discharged continuously or intermittently, while providing a duct for recovering combustible gas generated in the furnace body, on the ceiling or side of the hot metal gutter It is a smelting reduction facility characterized in that a burner is provided and a gas pipe branched from the duct is connected to the burner, and the present invention also provides that the molten metal passes through a molten metal outlet through a molten metal gutter through a molten metal reservoir. To the hot metal pot, the slag from the slag outlet to the slag pan through the slag gutter, in the equipment to directly produce molten metal that is discharged continuously or intermittently,
A smelting reduction facility characterized in that a duct for collecting combustible gas generated in the furnace body is provided, a burner is provided above the hot metal pot, and a gas pipe branched from the duct is connected to the burner.

[0028] The present invention also provides a method of manufacturing a furnace in which a metal raw material, a carbon material,
And slag-making material is added, and pure oxygen and / or oxygen-enriched gas is blown therein. A molten metal is stored at the bottom of the furnace body, and a slag having a specific gravity lower than that of the molten metal is stored at the upper portion thereof.
In the method of directly producing molten metal from a tap hole through a molten metal reservoir and slag from a tap hole continuously or intermittently, the temperature of the molten metal reduced in the furnace body is determined. Is set lower than the temperature of the molten metal discharged from the taphole, in the molten metal pool, by heating the molten metal by a burner, to raise the temperature to the temperature of the molten metal discharged from the taphole. It is a method of operating a smelting reduction facility characterized by the following features.Molten metal is continuously transferred from a spout through a molten metal gutter to a hot metal pot through a molten metal pool, and slag is continuously transferred from a slag outlet to a slag pan through a slag gutter. Alternatively, in the method for directly producing molten metal that is intermittently discharged, the temperature of the molten metal reduced in the furnace body is set lower than the temperature of the molten metal required in the lower process, And / or in a hot metal ladle, a method for operating a smelting reduction facility, wherein the temperature of the molten metal is raised to the temperature of the molten metal required in the lower step by burner heating. A part of the combustible gas generated in the furnace body.

The smelting reduction equipment of the present invention has the following effects by adopting the above-described configuration. The temperature of the molten metal in the furnace main body can be lowered, and the temperature of the molten metal in the furnace main body, the slag temperature and the temperature of the combustible gas discharged from the furnace main body can be reduced accordingly, and the carbon material and Oxygen intensity decreases. The temperature of the slag can be lowered, and the amount of heat removed from the water-cooled panel in the range facing the slag on the inner surface of the furnace body is reduced, and the carbon material and the oxygen consumption are reduced by the amount of the heat.

The temperature of the combustible gas discharged from the furnace main body can be reduced, and the heat removal of the water-cooled panel in the area facing the upper space on the inner surface of the furnace main body decreases. descend. The temperature of the molten metal and the slag in the furnace main body can be lowered, the wear rate of the refractory in the range facing the molten metal and the slag on the inner surface of the furnace main body is reduced, and the frequency and cost of repairing the refractory are reduced. Even if the temperature of the molten metal is increased in the hot metal pool, there is no slag in the hot metal pool, so there is no concern about a large increase in the wear rate of the refractory.

The temperature of the molten metal and the slag in the furnace body can be lowered, and the dephosphorization ability is improved. Even if the temperature of the molten metal is increased in the hot metal pool, there is no slag in the hot metal pool, so there is no fear of rephosphorization. By using a part of the combustible gas generated in the furnace body as the fuel for the burner, there is no need to supply the burner fuel from outside the system. Regardless of fluctuations in the temperature of the molten metal discharged from the taphole specified from the down stroke, by keeping the temperature of the molten metal in the furnace body low and constant, the carbonaceous material resulting from the fluctuation in the specified temperature and There is no need to change the oxygen input.

[0032]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a vertical sectional view of a furnace body structure of one embodiment of a smelting reduction facility according to the present invention, and FIG.
It is -A sectional drawing. The furnace main body 1 is fixed to a foundation 2, a water cooling panel 3 and a refractory 4 are lined on the inner surface of the furnace main body, and a raw material for adding an iron raw material, a carbonaceous material, and a slag-making material is placed on the upper part of the furnace main body 1. A port 5 and a gas discharge port 6 for discharging combustible gas generated from the furnace body are provided. Furnace body 1
A hot metal 7 is stored at the bottom of the slag, and a foamed slag 8 having a lower specific gravity than the hot metal 7 is stored at an upper portion of the hot metal 7.

The hot metal 7 is transferred from the furnace body 1 to the hot metal tunnel 1.
The hot metal flows into the hot metal pool 9 through the metal pool 7. Since the hot metal tunnel 17 is open at a height below the interface between the foamed slag 8 and the hot metal 7, the slag does not flow into the hot metal pool 9, and only the hot metal 7 is stored.

The burner 2 is provided at the ceiling of the hot metal pool 9.
6 is provided to heat the hot metal 7. After the hot metal 7 is heated to the temperature specified in the lower process as described above, the tap hole 11 provided near the upper surface of the hot metal 7 in the hot metal pool 9
Is discharged continuously or intermittently. In the hot metal pool 9,
A relatively low temperature hot metal flows from the hot metal tunnel 17, that is, from below, and the upper surface of the hot metal 7 is heated by the burner flame, and the heated hot metal is discharged from the upper tap hole 11. Is expensive. On the other hand, the slag is continuously or intermittently discharged from the slag port 12 through the slag tunnel 18 and the slag reservoir 10.

The high temperature combustible gas generated in the furnace body 1 is
After being guided to a gas cooler 19 through a gas discharge port 6 provided at an upper portion of the furnace main body 1 and lowering the temperature of the combustible gas, the gas holder 23 is subjected to final combustion through a dust collector 20, a blower 21, a duct 22, and the like. Stored in

A part of the recovered combustible gas is supplied to the duct 2
The gas is supplied to a burner 26 via a gas pipe 24 and a booster 25 branched from the second. Oxygen and / or air are also supplied to the burner 26 via another pipe, and burn together with the combustible gas to heat the hot metal 7 in the hot metal pool 9.

(Embodiment 2) An embodiment of the present invention will be described below with reference to FIG. FIG. 6 is a vertical sectional view of a furnace body structure of another embodiment of the smelting reduction facility according to the present invention. The structure of the furnace main body is basically the same as that of Example 1 except for the structure of the melting tub and / or the melting pot. Hot metal 7 in hot metal pool 9
A muzzle outlet 11 is provided near the upper surface of the hot metal ladle 28 so as to be continuously or intermittently discharged to the hot metal ladle 28 through the hot metal gutter 27.

A hot metal gutter burner 29 and / or a hot metal pot burner 30 are provided on the ceiling or side surface of the hot metal gutter 27 and / or the ceiling of the hot metal ladle 28, respectively, to heat the hot metal 7. The hot metal 7 is transported to the lower process after being heated to the temperature specified in the lower process.

The hot metal 7 having a relatively low temperature flows out of the outlet 11 into the hot metal gutter 27, and the upper surface of the hot metal 7 is placed on the hot metal gutter burner 2.
9 and / or heated by the flame of the hot metal pot burner 30.

The high-temperature combustible gas generated in the furnace body 1 is
After being guided to a gas cooler 19 through a gas discharge port 6 provided at an upper portion of the furnace main body 1 to lower the temperature of the combustible gas, the gas holder 23 is kept unburned through a dust collector 20, a blower 21, a duct 22, and the like. Stored in

A part of the unburned combustible gas collected in the gas holder 23 is passed through a gas pipe 24 branching from the duct 22 and a booster 25 to a hot metal gutter burner 29.
And / or supplied to the hot metal pot burner 30. Oxygen and / or air is also supplied to the hot metal gutter burner 29 and / or the hot metal ladle burner 30 through another pipe, and is burned together with the combustible gas to form the hot metal 7 of the hot metal gutter 27 and the hot metal ladle 28.
Heat.

The following table shows an example of the prior art proposed in Japanese Patent Application Laid-Open No. 1-502276 and an example of the carbonaceous material and the oxygen consumption rate of the smelting reduction facility according to the present invention. The operating conditions are as follows. Molten metal raw material: Iron ore Carbon material type: Steam coal Hot metal production rate: 25 t / h Tapping temperature: 1500 ° C Burner gas composition: CO ₂ CO ₂ H ₂ H ₂ ON ₂ 33% 26% 12% 19% 9%

[0043]

[Table 1]

As described above, about 100 to 2
By raising the temperature by 00 ° C, the hot metal temperature in the furnace
２００200 ° C., and the calorific value of the combustible gas is about 9-17
%, The heat removal from the water-cooled panel is reduced by about 18-34%, and as a result, the carbon unit consumption is about 8-15% and the oxygen consumption is 12-
There was an effect of reducing by 23%.

Further, the hot metal temperature in the furnace body is set to about 100 to 2
By being able to lower by 00 ° C., the dephosphorization ability was improved, and [P] in the hot metal was reduced by 11 to 32%. Further, the amount of wear of the refractory was reduced by 70 to 80%. In addition, since the power consumption of the oxygen facility was reduced due to the decrease in the oxygen consumption rate, the power consumption of the entire smelting reduction facility was reduced by about 11 to 20%.

In this embodiment, the case of reducing iron has been described. However, the present invention provides a non-ferrous metal and an iron alloy (for example, chromium, nickel,
Needless to say, the present invention is also applied to a smelting reduction facility for manganese or the like. Further, in the present embodiment, the case where the horizontal cross section of the furnace body is a smelting reduction facility having a rectangular shape,
It goes without saying that the present invention is also applied to a smelting reduction facility in which the horizontal cross section of the furnace body is circular.

[0047]

According to the smelting reduction facility of the present invention, the following effects can be expected by adopting the above-mentioned structure. The temperature of the molten metal in the furnace body can be lowered, and the temperature of the molten metal in the furnace body, the slag temperature, and the temperature of the combustible gas discharged from the furnace body can be reduced accordingly. Intensity decreases. The temperature of the slag can be lowered, and the amount of heat removed from the water-cooled panel in the range facing the slag on the inner surface of the furnace body is reduced, and the carbon material and the oxygen consumption are reduced by the amount of the heat.

The temperature of the combustible gas discharged from the furnace main body can be reduced, and the heat removal of the water-cooled panel in the area facing the upper space on the inner surface of the furnace main body decreases. descend. The temperature of the molten metal and the slag in the furnace main body can be lowered, the wear rate of the refractory in the range facing the molten metal and the slag on the inner surface of the furnace main body is reduced, and the frequency and cost of repairing the refractory are reduced. Even if the temperature of the molten metal is increased in the hot metal pool, there is no slag in the hot metal pool, so there is no concern about a large increase in the wear rate of the refractory.

The temperature of the molten metal and the slag in the furnace body can be lowered, and the dephosphorization ability is improved. Even if the temperature of the molten metal is increased in the hot metal pool, there is no slag in the hot metal pool, so there is no fear of rephosphorization. By using a part of the combustible gas generated in the furnace body as the fuel for the burner, there is no need to supply the burner fuel from outside the system.

[0050] Irrespective of the fluctuation of the temperature of the molten metal discharged from the taphole specified from the down stroke, the temperature of the molten metal in the furnace body is kept low and constant, thereby causing the fluctuation of the specified temperature. There is no need to change the carbon and oxygen inputs. A relatively low temperature molten metal flows into the molten metal pool from a molten metal tunnel, that is, from below, the molten metal is heated from above by a burner flame, and the heated molten metal is discharged from an upper tap hole. Therefore, the heat efficiency of burner heating is high.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a furnace body structure of a first embodiment of a smelting reduction facility according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a vertical sectional view of a furnace structure of a smelting reduction facility according to a conventional technique.

FIG. 4 shows the relationship between molten metal temperature and refractory wear.

FIG. 5 is a relation between molten metal temperature and phosphorus distribution.

FIG. 6 is a vertical sectional view of a furnace body structure of Embodiment 2 of the smelting reduction facility according to the present invention.

[Explanation of symbols]

 1: Furnace body 2: Foundation 3: Water-cooled panel 4: Refractory 5: Raw material inlet 6: Gas outlet 7: Hot metal 8: Foamed slag 9: Hot metal pool 10: Slag pool 11: Tap hole 12: Slag port 13: lower tuyere 14: upper tuyere 15: upper space 16: calming slag 17: hot metal tunnel 18: slag tunnel 19: gas cooler 20: dust collector 21: blower 22: duct 23: gas holder 24: gas pipe 25 : Booster 26: Burner 27: Molten tub 28: Hot metal pot 29: Hot metal pit burner 30: Hot metal pot burner

Claims (6)

[Claims] Claims 1. A metal raw material, a carbon material, and a slag material are added to a furnace body, and pure oxygen and / or an oxygen-enriched gas are blown into the furnace body.
Molten metal accumulates at the bottom of the furnace body, and slag having a lower specific gravity than the molten metal accumulates at the top.Molten metal is continuous or intermittent from the tap hole through the molten metal reservoir and slag from the slag port. In a facility for directly producing molten metal that is discharged directly, a duct for recovering combustible gas generated in the furnace body is provided, and a burner is provided on the ceiling or side surface of the molten metal reservoir, and a gas pipe branched from the duct is provided. Is connected to the burner. 2. A metal raw material, a carbon material, and a slag material are added to a furnace body, and pure oxygen and / or an oxygen-enriched gas are blown into the furnace body.
Molten metal accumulates at the bottom of the furnace body, and slag with a lower specific gravity than the molten metal accumulates at the top of the furnace.Molten metal passes through the molten metal reservoir from the spout through the hot metal gutter to the hot metal pot, and the slag is slag. From the mouth to the slag pan through the slag gutter, in a facility for directly producing molten metal that is discharged continuously or intermittently, in addition to providing a duct for collecting combustible gas generated in the furnace body, the ceiling of the hot metal gutter or A smelting reduction facility, wherein a burner is provided on a side surface, and a gas pipe branched from the duct is connected to the burner. 3. A metal raw material, a carbon material, and a slag material are added to a furnace body, and pure oxygen and / or an oxygen-enriched gas is blown into the furnace body.
Molten metal accumulates at the bottom of the furnace body, and slag with a lower specific gravity than the molten metal accumulates at the top of the furnace.Molten metal passes through the molten metal reservoir from the spout through the hot metal gutter to the hot metal pot, and the slag is slag. From the mouth to the slag pan through the slag gutter, in a facility for directly producing molten metal that is discharged continuously or intermittently, in addition to providing a duct for collecting combustible gas generated in the furnace body, above the hot metal pot A smelting reduction facility, wherein a burner is provided, and a gas pipe branched from the duct is connected to the burner. 4. A metal raw material, a carbon material, and a slag material are added to a furnace body, and pure oxygen and / or an oxygen-enriched gas is blown therein.
Molten metal accumulates at the bottom of the furnace body, and slag having a lower specific gravity than the molten metal accumulates at the top.Molten metal is continuous or intermittent from the tap hole through the molten metal reservoir and slag from the slag port. In the method for directly producing molten metal that is discharged directly, the temperature of the molten metal that is reduced in the furnace body is set lower than the temperature of the molten metal that is discharged from the taphole, and in the molten metal pool, And operating the molten metal to a temperature of the molten metal discharged from the taphole by burner heating. 5. A metal raw material, a carbon material, and a slag-making material are added to a furnace body, and pure oxygen and / or an oxygen-enriched gas are blown into the furnace body.
Molten metal accumulates at the bottom of the furnace body, and slag with a lower specific gravity than the molten metal accumulates at the top of the furnace.Molten metal passes through the molten metal reservoir from the spout through the hot metal gutter to the hot metal pot, and the slag is slag. In a method for directly producing molten metal that is continuously or intermittently discharged from a mouth to a slag pan through a slag gutter, the temperature of the molten metal reduced in the furnace main body is set to the temperature of the molten metal required in the lower step. A method for operating a smelting reduction facility, wherein the temperature is set lower than a temperature, and the molten metal is heated to a temperature of the molten metal required in the lower step by burner heating in the molten metal gutter and / or the molten metal ladle. 6. The method for operating a smelting reduction facility according to claim 4, wherein a part of the combustible gas generated in the furnace body is used as fuel for the burner for heating the molten metal.