JPH10317029A - Smelting reduction furnace for iron raw material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a smelting reduction furnace, in which the heat load on the furnace wall is reduced and while preventing the reoxidation of reduced metallic iron, the improvement of productivity and lowering of the unit requirement of solid carbon are realized. SOLUTION: In the smelting reduction furnace for iron raw material arranging plural lower tuyeres 4 and upper tuyeres 5 at both sides of the lower part and the upper part of a reaction vessel, respectively and a molten iron pool part and a slag pool part at the lower part of the reaction vessel 1, plural projections 14 or grooves 15 forming horizontal steps on the wall surface at the intervals at the upper part from the lower tuyeres 4 in molten slag part of the water-cooling furnace wall 13 in the reaction vessel 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an iron for directly producing molten iron or pig iron by putting an iron raw material and a carbonaceous material into a slag bath for smelting reduction, and blowing oxygen or oxygen-enriched air into the slag bath. The present invention relates to a smelting reduction furnace for raw materials.

[0002]

2. Description of the Related Art In the smelting reduction method of iron ore, an iron raw material, a carbonaceous material and a slag-making agent are placed in a reaction vessel of a smelting reduction furnace comprising a reaction vessel, a hot metal reservoir and a slag reservoir communicating with the reaction vessel at a siphon opening. The slag bath is stirred by oxygen or oxygen-enriched air blown from the lower tuyere provided on the side wall of the reaction vessel to advance the reduction reaction, and the iron raw material, the carbonaceous material and the slag-making agent are introduced into the slag bath. This is a method for directly producing molten iron or pig iron by mixing and reducing the iron raw material and separating the produced iron or pig iron from slag.

FIG. 4 shows a conventional smelting reduction furnace, and FIG.
Is a front cross-sectional view, and FIG. 4- (b) is a side cross-sectional view. In the upper part of the reaction vessel 1, a raw material input for charging a raw material such as an iron raw material, a carbon material, and a slag-making material into the reaction container 1 is performed. A hole 2 and a gas outlet 3 for discharging gas generated in the reaction vessel 1 are provided, and the gas outlet 3 is connected to a boiler for recovering heat of exhaust gas.

A plurality of lower tuyeres 4 and upper tuyeres 5 are provided on both lower and upper sides of the reaction vessel 1, respectively. Oxygen-enriched air is supplied from the lower tuyeres 4 and oxygen is supplied from the upper tuyeres 5 respectively. It is blown into 1.

[0005] On the left and right outside of the lower portion of the reaction vessel 1, a hot metal pool 7 is provided on one side thereof, which communicates with the reaction vessel 1 through a siphon port 6a. Tap hole 9 is provided. On the other side, a slag reservoir 10 communicating with the reaction vessel 1 at the siphon port 6b is provided, and the slag reservoir 10 is provided with a slag outlet 12 for discharging the slag 11.

The process for producing iron or pig iron using the above-described smelting reduction furnace will be described. Iron raw materials, carbon materials such as coal or coke, and raw materials such as slag-making agents are continuously supplied from a raw material charging hole 2 to a reaction vessel 1. It is thrown in.

[0007] In the reaction vessel 1, 14
A slag bath 11a of 00 to 1500 ° C. is formed, and oxygen-enriched air is blown into the slag bath 11a through the lower tuyere 4 to stir the slag bath 11a,
A part of the input coal is burned to supply heat to the slag bath 11a. The charged raw material is caught and melted in the slag bath 11a, and the iron oxide in the slag is reduced by the coal.

Gas (CO gas) emitted from the slag bath 11a
Oxygen from upper tuyere 5 to 1500-180
The secondary combustion heat of 0 ° C. is generated, and the secondary combustion heat can be efficiently transmitted to the slag bath 11a.

Below the lower tuyere 4 there is a slag layer with a gentle movement where the iron or pig iron droplets and the slag 11 are separated, and the iron or pig iron 8 passes through the siphon port 6a and the molten iron pool 7 The slag 11 is discharged out of the furnace through the tap hole 9 and the slag 11 is discharged from the slag reservoir 10 through the tap hole 12 through the siphon port 6b. When oxygen is blown from below the slag, carbon is combusted in the slag, so that the slag has a high heat transfer efficiency to the slag and a large stirring effect.

[0010]

However, the high-temperature gas generated by burning the solid carbon entrained in the slag with oxygen blown from the lower tuyere increases the heat load on the furnace wall. To avoid this, it was necessary to discharge the blowing gas containing oxygen at a high speed from the lower tuyere and keep it away from the furnace wall. As a result, the gas is blown up to the center of the furnace and the oxidation zone expands, preventing the formation of a reduction zone in which solid carbon stays.Moreover, most of the metallic iron generated during the sedimentation passes through the oxidation zone below. It had the disadvantage that it was reoxidized and the production rate did not increase.

Further, there is also a disadvantage that the entire slag in the furnace is formed, the stagnation of solid carbon is prevented, and a reduction zone is hardly formed.

The present invention provides a smelting reduction furnace which reduces the heat load on the furnace wall, prevents reoxidation of reduced metallic iron, and improves the productivity and reduces the solid carbon unit consumption. is there.

[0013]

A smelting reduction furnace for an iron raw material according to the present invention is provided with a plurality of lower tuyeres and upper tuyeres on both sides of a lower part and an upper part of a reaction vessel, respectively. In the slag reservoir, a slag reservoir is provided in the smelting reduction furnace of the iron raw material, and a plurality of protrusions or a plurality of protrusions forming a horizontal step on the wall surface at a distance above the lower tuyere in the slag bath portion on the water cooling furnace wall of the reaction vessel. A feature is that a groove is formed.

[0014]

FIG. 1 is a front sectional view of a smelting reduction furnace according to the present invention. In the present invention, the structure of the reaction vessel, the hot metal pool and the slag chamber, and the arrangement of the tuyere constituting the smelting reduction furnace main body, excluding the water-cooled furnace wall of the reaction vessel, have been described with reference to FIG. It has the same structure as the main body of the smelting reduction furnace, and the same parts are denoted by the same reference numerals, and description thereof is omitted.

A plurality of protrusions 14 or grooves 15 are formed on the wall of the water-cooled furnace 13 of the reaction vessel 1 at intervals above the lower tuyere 4 in the slag bath portion to form horizontal steps on the wall surface. The projection 14 or the groove 15 is preferably provided on the entire circumference of the reaction vessel. The water-cooled furnace wall 13 is made of a material having good heat conductivity, for example,
It is preferable to use a copper-based metal.

FIG. 2A, FIG. 2B and FIG.
(A) is a longitudinal sectional view showing various embodiments of a water-cooling furnace wall of the present invention, and FIGS. 3- (b) and 3- (c) are perspective views of a water-cooling element.

FIG. 2A shows that the projection 14 or the groove 15 forming the horizontal step is formed integrally, and the cooling water channel 1 is formed on the projection 14.
6 is an example of a water-cooled furnace wall 13 provided with a water-cooled furnace wall 6.

FIG. 2B and FIG. 3A show an example in which a projection 14 for forming a horizontal step is formed by combining water cooling elements 17a and 17b having a cooling water passage 16. The water-cooling element is shown in FIG. 3- (b) and FIG. 3- (c)
As shown in FIG. 3, the bar is made of copper and has a cooling water passage 16.

The smelting reduction process of the iron raw material by the smelting reduction furnace of the present invention will be described.

In the smelting reduction of the iron raw material by the smelting reduction furnace of the present invention, the production process of iron or pig iron and slag in the reaction vessel is the same as the production process described in the aforementioned “prior art”. Pig iron produced by the reduction in the bath accumulates in the molten iron pool through the siphon opening, and slag accumulates in the slag reservoir through the siphon opening.

In FIG. 1, an iron raw material is reduced in a reduction zone 18 by solid carbon, and a metallic iron stream 19 flows through a slag bath.
It sinks down. Lower tuyere 4 for slag bath 11a
Oxygen-enriched air is blown through the slag bath 11a to cause secondary combustion of a small amount of solid carbon in the slag bath 11a to perform secondary combustion.
And the gas 20 containing unburned oxygen rises.

The protrusion 1 forming the horizontal step of the water-cooled furnace wall 13
The groove 4 or the groove 15 prevents the free flow of the molten slag stream 21 in contact therewith, so that the amount of heat transfer between the gas-water cooled furnace walls is reduced, and the flow of the molten slag stream 21 in contact with the furnace walls is prevented. In order to reduce the heat load, only the vicinity of the furnace wall is agitated, and the reduction zone 18 can be formed at the center of the molten slag bath, so that reoxidation of the reduced metallic iron can be prevented.

[0023]

The heat load on the furnace wall is reduced by the projections or grooves forming the horizontal steps of the water cooling wall, so the amount of heat taken from the water cooling wall is reduced, the thermal efficiency of the process is improved, and the unit consumption of coal is reduced. it can.

According to the present invention, since reoxidation of reduced metallic iron can be prevented, productivity is improved, and carbon lost due to reoxidation of metallic iron is reduced, and a reduction in unit consumption of coal can be realized.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a smelting reduction furnace of the present invention.

FIG. 2 is a longitudinal sectional view showing an embodiment of a water-cooled furnace wall of the present invention.

FIG. 3A is a longitudinal sectional view showing an embodiment of a water-cooling furnace wall according to the present invention, and FIGS. 3B and 3C are perspective views of a water-cooling element.

4 (a) is a front sectional view and FIG. 4- (b) is a side sectional view of a conventional smelting reduction furnace.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction container 2 Raw material input hole 3 Gas discharge port 4 Lower tuyere 5 Upper tuyere 6a, 6b Siphon port 7 Hot metal pool 8 Hot metal 9 Tap hole 10 Slag pool 11 Slag 11a Slag bath 12 Tap hole 13 Water cooling furnace wall 14 Projection 15 Groove 16 Cooling channel 17a, 17b Water cooling element 18 Reduction zone 19 Metal iron flow 20 Gas containing unburned oxygen 21 Molten slag flow

Claims (1)

[Claims] 1. A smelting reduction method for an iron raw material in which a plurality of lower tuyeres and upper tuyeres are provided on both sides of a lower part and an upper part of a reaction vessel, respectively, and a molten iron pool and a slag pool are provided at a lower part of the reaction vessel. A smelting reduction furnace for an iron raw material, wherein a plurality of projections or grooves are formed on a wall of a water-cooled furnace of a reaction vessel at a distance above the lower tuyere at a slag bath portion to form a horizontal step on the wall. .