JPH11131116A - Method of vertical cupola, blast furnace, and melting furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce equipment cost and to utilize finely powdered raw material by forming layers of a raw iron ore and coke on an upper part of a tuyere provided on a lower part of the furnace, providing an empty tank inside of a shaft on its upper part to reduce the speed of the combustion gas to prevent the blow-up of the dust. SOLUTION: In a vertical shaft cupola, blast furnace and melting furnace in which a plurality of tuyeres 7 are provided in a belly 4 above a hot metal hearth 2 and a slag floor 3 of a hearth 1, and a shaft 5 is provided thereabove, the raw material 9 such as iron ore, coke and lime is charged from a furnace top 10 through a conveyor 12, a throw-in hopper 13, etc., a raw material layer 24 is formed above the tuyeres 7 at a lower part of the furnace, and the inside of the shaft 5 is an empty tank 25. The distance (h) between the tuyeres 7 and a raw material charging surface 15 is approximately >=1/2 of the height between the tuyeres 7 and the furnace top 10. Hot air is fed from the tuyeres 7 to form a raceway 8, and the iron is reduced to obtain the hot metal. The speed of the combustion gas is greatly reduced, and a large gas ash dust settling device is dispensed with.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical shaft cupola, a blast furnace, and a melting furnace method for melting iron ore and extracting pig iron.

[0002]

2. Description of the Related Art As a conventional blast furnace melting furnace, as shown in FIG. 3, a hearth 1 laid with refractory bricks is formed, and a hot metal bed 2 is provided on the upper part so that molten pig iron is collected.
A slag bed 3 for separating slag is provided at an upper part thereof, and a furnace belly 4 formed of refractory brick is provided so as to surround them.
The shaft 5 is formed by stacking refractory bricks integrally on the upper part thereof, and the periphery thereof is surrounded by an iron plate 6 and protected. The furnace wall is provided with several tens of tuyeres 7 for feeding hot air, and is formed so that heat can be completely transmitted through the raceway 8 in the furnace. The high-temperature hot air blown from here becomes a combustion gas passing between the iron ore raw material and the coke (for example, 25 layers each) in the multi-stage layer 9A, reduces the iron ore, melts and removes pig iron down. At the same time, the gas is collected from the furnace top 10 to the blast furnace gas riser 11. In addition, the slag is also taken out of the system. The charging of the raw material 9 such as iron ore, coke, limestone and the like is carried to the upper furnace top 10 by the belt conveyor 12 and thrown into the hopper 13. It is replenished up to 15. The furnace temperature is higher in the lower part, and about 2,000
High temperature of 0 ° C. 16 is a blast furnace support, 17 is a hot blast tube, 18 is a gas ash dust settling device, 19 is a taphole, 20
Is a torpedo car for carrying pig iron out therefrom, 21 is a slag outlet, 22 is a slag wheel, and 23 is a hot-air annular tube.

[0003]

In a conventional blast furnace, a multistage layer of iron ore and coke is clogged in the shaft, and the air supplied from the tuyere burns coke at a raceway to about 2,000. It becomes a mixed gas of carbon monoxide and carbon dioxide gas at a high temperature of ℃, and is discharged from the furnace top while passing through the upper multi-layer. It is transported from the top to a gas ash dust sedimentation device (dust catcher). Therefore, a gas ash dust sedimentation device is indispensable, and its accuracy must be high, so that there has been a problem that the equipment cost is high.

[0004] Accordingly, when the raw material contains fine powder, there is also a problem that a large amount of the fine powder is suspended in gas and discharged. For this reason, the raw material containing a large amount of fine powder sometimes needs to be processed into sinter or pellet processing.

[0005] In view of the above problems, the present invention provides a melting furnace method in which dust such as fine powder is not discharged from the furnace as much as possible, and has a function of a dust catcher inside the shaft. Things. Therefore, even when using from fine powder to granular raw material, it provides a revolutionary method with less dust discharged from the furnace top, without installing a separate dust catcher or increasing the size, and equipment cost is also reduced. It is cheaper. The result is a reduction in the amount of industrial waste dust generated.

[0006]

In order to solve the above-mentioned object, a raw material layer is positioned above a tuyere provided at the lower part of a furnace (morning glory) and as much as possible below a shaft, and an empty tank is provided above the shaft. Is provided as much as possible, and the inside of the shaft is used as an empty tank to reduce the gas velocity of the empty tank and sediment and collect dust in this empty tank.

Further, since no dust is emitted to the outside of the system, even a raw material having a large amount of fine powder is used without being subjected to sinter processing or pellet processing.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on embodiments with reference to the drawings. In FIG. 1, the hearth 1
Is formed by placing a refractory brick thereon, and a furnace belly 4 is surrounded on the upper part so as to form a hot metal bed 2 and a slag bed 3 where molten pig iron accumulates. There is a shaft 5 having a structure in which sexual bricks are piled up, and the entire blast furnace is surrounded by an iron plate 6 or the like to strengthen and protect it. Iron ore, coke, limestone 7 and the like 7 are charged from a furnace top 10 of a blast furnace by a raw material charging belt conveyor 12. Reference numeral 13 denotes a charging hopper for sequentially charging iron ore, coke, and limestone in accordance with an instruction signal. Reference numeral 24 denotes a layer of raw iron ore and coke in the furnace. The lowermost position is formed above the tuyere 7, and an empty tank 25 is formed in the shaft above the uppermost stage. Settlement tank.

When hot air is sent from dozens of tuyeres 7 opened in the furnace wall, the heat is completely distributed through the raceway 8 in the furnace. The high-temperature hot air blown from here passes through the stepped raw material ore and coke to reduce and melt the iron ore and drop pig iron down. Also, the accumulated slag is taken out of the system. Large empty tank 25 in the upper part of the furnace
Since there are few steps of iron ore and coke, the speed of the combustion gas is about 1 times lower than that of the conventional combustion gas.
/ 3 to 1/10 or less, and no dust is blown up. That is, it does not reach the furnace top.

FIG. 2 shows the correlation between the height (Hm) from the tuyere to the charged material surface at the furnace top and the amount of gas ash dust discharged and scattered from the furnace top (Wg / Nm ³ ) in the blast furnace. The vertical axis represents the amount of scattering and the horizontal axis represents the height, and is expressed in% in comparison with the conventional example. H indicates the height to the conventional charged material surface as 100%. The height at which the discharge of gas ash dust from the furnace top becomes abruptly small is 1/2 H. This point is about a half of the conventional value in terms of the amount of scattered discharge.
Below this, it approaches a state where there is almost no emission. That is, if the height set in the present invention is h, h ≦ 1
/ 2H satisfies the expression (1).
Thus, in the present invention, the empty tank 25 in the shaft is set.

FIG. 3 is a correlation diagram based on an empirical rule when determining the height H from the tuyere to the material charging surface, and shows the relationship with the hearth diameter D at the time of design. It is obtained by the formula. H = 1.5D + 5 (2) From this, the height h of the present invention is determined so as to satisfy the expressions (1) and (2). It is known from experience that the height of the furnace top is designed to be 1.5 to 3.0 meters above the height of H. From these, an estimate of the overall design can be made.

Conventionally, it is possible to use fine powder constituting most of the dust or fine iron ore called pellet feed as it is, and it is also possible to use sinter ore processing or pellet processing.

[0013]

Since the present invention is configured as described above, it has the following effects.

[0014] A large-scale gas ash dust sedimentation device such as that of the related art is not required, and the equipment cost can be reduced.

[0015] Further, since the structure is such that the fine powder is hardly discharged, it is possible to use not only fine iron ore but also steel dust such as converter dust, electric furnace dust, and oil-containing rolling scale powder. In the case of a raw material having many fine powders, the trouble of sintering or pellet processing can be omitted.

Generated as industrial waste in the iron mining industry,
Steel dust such as converter dust, electric furnace dust and oil-impregnated rolling scale powder can also be treated in a blast furnace. The ability to treat various dusts in this way has a great advantage in resource recycling.

Furthermore, industrial waste such as low-grade shredder waste and shredder dust can be used as recycled resources by using the melting furnace method of the present invention.

[Brief description of the drawings]

FIG. 1 is a schematic partial sectional view of a vertical shaft blast furnace according to one embodiment of the present invention.

FIG. 2 is a diagram showing the correlation between the height from the tuyere to the surface of the charged material at the furnace top and the amount of gas ash dust discharged and scattered from the furnace top.

FIG. 3 is a correlation diagram based on an empirical rule with a hearth diameter D when a height H from a tuyere to a raw material charging surface is determined.

FIG. 4 is a schematic partial sectional view of a conventional general vertical shaft blast furnace.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace bed 2 Hot metal bed 3 Slag bed 4 Furnace belly 5 Shaft 7 Tuyere 8 Raceway 9 Raw material 15 Raw material loading surface 24 Layer of raw iron ore and coke in furnace 25 Empty tank H Furnace top from tuyere Height from the surface of the raw material h Height from the tuyere to the surface of the raw material in the shaft

Claims (1)

[Claims] 1. In a vertical shaft cupola, a blast furnace, and a melting furnace having a furnace belly surrounding an upper part of a hearth to form a hot metal bed and a slag bed and a shaft at the upper part thereof, a tuyere provided at a lower part of the furnace is provided. A vertical shaft cupola, blast furnace, and melting furnace method in which a layer of iron ore raw material and coke is formed in the upper part, and the inside of the shaft is an empty tank to melt the iron ore raw material at a high temperature and take out pig iron. .