JPH0570818A - Multi-step tuyere type smelting reduction furnace - Google Patents

Abstract

(57) [Summary] [Structure] Multi-stage tuyere smelting reduction furnace with a gas impermeable member made of gas-impermeable refractory material in the center of the hearth [Effect] Pig iron by multi-stage tuyere smelting reduction furnace In addition, the gas utilization rate in the production of ferroalloys can be improved, the number of hangings can be reduced, the consumption of carbonaceous materials can be reduced, and stable operation can be achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical type smelting reduction furnace (hereinafter referred to as a multi-stage tuyere type smelting reduction furnace), which is provided at least in two stages above and below and each has a plurality of tuyere. The present invention relates to a multi-stage tuyere type smelting reduction furnace in which a gas impermeable member made of a refractory material is arranged in a central portion.

[0002]

2. Description of the Related Art Conventionally, the operation technique of a multi-stage tuyere type smelting reduction furnace is disclosed in Japanese Examined Patent Publication No. 59-18453 and Japanese Examined Patent Publication No. 59-28.
605, JP-A-63-153208, JP-A-62-227015, and JP-A-64-47820.
JP-A-64-62408, JP-A-64-62408
No. 213, etc. To summarize these technologies, a packed bed or fluidized bed of solid carbonaceous reducing agent is formed in the lower part of the furnace, and the ore (including pre-reduced ore), flux, etc. blown from the upper tuyeres are contained in the front of the tuyeres. After being melted on the sway, the melt drips between the upper and lower tuyeres. The dripping melt is reduced by the CO gas generated by the reaction between the air blown from the lower tuyeres and the solid carbonaceous reducing agent, and remains in the hearth as molten pig iron or molten iron alloy.

The area to be melt-reduced is determined by the cross-sectional area of the raceway of the upper tuyeres and the flow path of CO gas generated in front of the lower tuyeres. That is, as shown in FIG. 3, tuyeres are evenly arranged on a circular furnace wall 2 to form a raceway 1 in front of the tuyeres, and an area A where the raceway cannot reach is formed in the central portion of the furnace body. .. This region A is a region that hardly participates in the smelting reduction reaction, and it tends to expand as the furnace body becomes larger. The presence of such an area A reduces the utilization rate of the blown gas or air, increases the number of times of hanging on the shelf,
It has an unfavorable effect on operation, such as an increase in the amount of carbonaceous material consumed.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a gas impermeable member made of a gas impermeable refractory material is arranged in the central portion of the hearth to provide the above-mentioned structure. It is an object of the present invention to provide a multi-stage tuyere type smelting reduction furnace capable of reducing unfavorable effects such as a decrease in the utilization rate of blown gas or air due to the presence of the region A and an increase in the number of times of hanging on a shelf. Is.

[0005]

The present invention is a vertical smelting reduction furnace which has a plurality of tuyere at least vertically in two stages and blows raw materials together with high temperature air from the tuyere in the central part of the hearth. A multi-stage tuyere-type smelting reduction furnace characterized in that a gas-impermeable member made of a refractory material is arranged at substantially the same height as the upper-stage tuyere.

[0006]

According to the present invention, a gas impermeable member made of a gas impermeable refractory material and having substantially the same height as the upper tuyeres is disposed in the central portion of the hearth, so that the air blown from the lower tuyeres can be prevented. It can be used for smelting reduction between the upper and lower tuyeres. Here, if the level of the gas impermeable member is lower than the level of the upper tuyeres, the gas from the lower tuyeres escapes to the center of the furnace, and if it is higher than the level of the upper tuyeres, Since the raceway is blown up and the upper raceway becomes smaller, it is necessary to make the height of the gas impermeable member the same as that of the upper tuyeres. The size (diameter) is
It may be about the same as the diameter of the area A where the sway does not reach.

Further, it is effective at the tapping work if a flow hole for facilitating the flow of molten pig iron is provided in the portion of the gas impermeable member which is in contact with the hearth. Here, the refractory material is not particularly limited, and any silicon carbide-based, chamotte-based, carbon-based, or other refractory material that is gas impermeable can be used. When installing, it may be fixed to the central part of the hearth according to a conventional method.

[0008]

1 is a schematic side view of a hearth part showing an embodiment of the present invention, and FIG. 2 is a schematic plan view thereof. That is, inner diameter 3m
A cylindrical gas impermeable member 3 having an outer diameter of 1.5 m was arranged in the center of the hearth. A flow hole 4 having a width of 0.75 m is provided in a portion of the gas-impermeable member 3 in contact with the hearth to facilitate the flow of the hot metal during tapping. Table 1 shows the operation results of the example in which the gas impermeable member 3 is provided and the operation results of the comparative example in which the gas impermeable member 3 is not provided. In addition, this example is an operation result when a chromium-containing pig iron containing 30% chromium is manufactured. As is clear from Table 1, the arrangement of the gas impermeable member according to the present invention has a remarkable effect in reducing the number of times of hanging on the shelf, reducing the consumption of carbonaceous material, and improving the gas utilization rate. ..

[0009]

[Table 1]

The gas impermeable member used in the examples is S
It was made of iC and was placed in the center of the hearth. Its size is a cylindrical shape that covers the area that the raceway does not reach, and its height is almost the same level as the upper tuyeres.

Although the packed bed type multi-stage tuyere type smelting reduction furnace for forming the packed bed of the solid carbonaceous reducing agent has been described above, the present invention is not limited to this and forms a fluidized bed or the like. It can also be applied to a non-packed bed type multi-stage tuyere type smelting reduction furnace.

[0012]

EFFECTS OF THE INVENTION In the multi-stage tuyere type smelting reduction furnace according to the present invention, since the gas impermeable member made of a gas impermeable refractory material is arranged in the central portion of the hearth, the heat of high temperature air blowing from the lower tuyere Was effectively transmitted to the melt, and the gas utilization rate could be greatly improved. Furthermore, since the consumption of solid carbonaceous material is uniform, the unloading in the furnace is stable, and the number of occurrences of rack hangings can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a schematic side view of a hearth portion of an example.

FIG. 2 is a schematic plan view of a hearth part of the embodiment.

FIG. 3 is a schematic plan view of a hearth part of a conventional example.

[Explanation of symbols]

 1 Raceway 2 Furnace wall 3 Gas impermeable member 4 Flow hole A Area where the raceway does not reach

Claims (1)

[Claims] 1. A vertical smelting reduction furnace having at least two upper and lower tuyeres in which the raw material is blown together with high-temperature air from the tuyeres, at the same height as the upper tuyeres at the center of the hearth. A multi-stage tuyere type smelting reduction furnace characterized in that a gas-impermeable member made of a refractory material is provided in the.