JPS5945725B2 - Vertical molten metal manufacturing furnace - Google Patents

Description

Detailed Description of the Invention The present invention involves charging a carbon-based solid reducing agent such as coal or coke from the upper part to form a packed bed, and a plurality of tuyeres provided in two upper and lower stages in the lower part. The present invention relates to a vertical molten metal manufacturing furnace configured to produce molten metal by blowing powdery ore or flux added thereto from at least the upper tuyere and melting and reducing the powdery ore. .

In this type of molten metal manufacturing furnace, the ore injected into the upper stage of the furnace is softened and melted at the tip of the upper tuyere.

Then, while descending toward the lower part of the furnace between the filled beds of carbon-based solid reducing agent, the molten ore is reduced by the reducing agent heated by the heat of combustion of the reducing agent at the tip of the lower tuyere, and the molten ore is reduced to molten metal and molten slag. separated into

In this case, what is important is that the ore injected from the upper tuyere descends without staying at the tip of the upper tuyere.

For this purpose, it was found that the packed bed of reducing agent at the tip of the upper tuyere also needed to descend smoothly.

An object of the present invention is to provide a molten metal manufacturing furnace in which ore injected from the upper tuyere can smoothly descend to the tip of the lower tuyere.

That is, the gist of the present invention is as follows.

A packed bed of carbon-based solid reducing agent is formed, and a plurality of layers are provided in the upper and lower layers at the bottom to reduce the
In a vertical furnace for producing molten metal from granular ore, the tuyere is melted and reduced by blowing granular ore together with high-temperature air from the upper tuyeres, or by adding flux to the tuyeres. Within a region forming an inverted cone with a vertical axis at an apex angle θ with the tip point as the apex, place the upper tuyere at a position where the lower tip of the upper tuyere corresponding to the lower tuyere satisfies the following formula. A vertical molten metal manufacturing furnace characterized by the installation of

θ≦0.64
) Hereinafter, the present invention will be explained in detail.

As shown in FIG. 1, in a vertical furnace 2 filled with a carbon-based solid reducing agent 1, the reducing agent burns at the tip of the lower tuyere 3 provided at the bottom. Area 4 is also provided.

The boundary line 5 forming the region 4 is determined by the apex angle θ of a right circular cone having the top end point of the lower tuyere 3 as its apex.

Therefore, if the upper tuyere 6 corresponding to the lower tuyere 3 is located within this area 4 when viewed from the circumferential direction of the furnace or from the vertical cross-sectional direction of the furnace as shown in FIG. It has been found that the ore injected from both ports 6 can smoothly descend to the corresponding lower tuyere 3 together with the reducing agent.

Note that 10 is the raceway. When operating the molten metal production furnace of the present invention to melt and reduce powdery ore, the particle size of the carbon-based solid reducing agent used is 5 to 100 m.
m is appropriate.

If the particle size is less than 5 mm, when the powder ore or flux injected from the tuyere becomes molten, the molten material drips through the voids in the packed bed of carbon-based solid reducing agent. Furthermore, the gas permeability of the packed bed is obstructed by the stagnant melt, which impedes the air blowing from the tuyeres and the gas flow in the furnace.

On the other hand, if the particle size exceeds 100 mfi, if the volume of the packed bed of carbon-based solid reducing agent is the same, the particle size will exceed 100 mfi.
Since the contact area between the melt and the carbonaceous material is reduced compared to the case of 1001 m or less, melt reduction becomes insufficient, and
It is difficult to obtain a carbon-based solid reducing agent with sufficient strength and the cost is high.

When the particle size of the carbon-based solid reducing agent (coke) used therein is 5 to 100 mm, an area where the upper tuyere 6 is installed corresponds to the lower tuyere 3 in the molten metal production furnace shown in FIG. 1 is formed. The maximum angle θ required for the ore injected from the upper tuyere 6 to smoothly descend with the reducing agent to the tip of the lower tuyere 3 is defined as the apex angle θ of the inverted cone whose apex is the top tip point of the lower tuyere 3. is the second particle size for the particle size of the reducing agent.
Plotted in the figure.

Approximate formula θ-0,64X dc +50 from each plot point
A straight line is derived.

In addition, in Figure 2, the particle size small on the horizontal axis is classified into various particle sizes, but when carrying out on an industrial scale, there is a particle size range to be used, for example, the average particle size is 50 mm. Even in this case, the maximum particle size may be around 100 mm.

Therefore, in the present invention, the apex angle θ of the inverted cone is determined by taking the particle size of the carbon-based solid reducing agent used as the maximum particle size.

As shown in Figure 2, the apex angle θ of the inverted cone is set within the area below the straight line, and the upper tuyere is installed so that its lower tip is located within the area of this inverted cone. if,
The molten ore flux injected from the upper tuyere can smoothly descend toward the tip of the lower tuyere together with the carbon-based solid reducing agent.

Example Using a coke particle size of 10 to 15, the upper layer was (a) installed within the area according to the present invention (θ = 50°), and (b) installed outside the same area (θ - 70°). °) K, an experiment was conducted to produce ferrochrome by injecting chromium ore into the upper siding.

The results are shown in the table below.

During the experiment (a), the chromium ore injected into the upper tuyere of the blowing pipe 7 was observed to dissolve smoothly through the peephole 8, and the produced metal was also in good condition.

During the experiment (b), when observing eight peep holes, softened and molten ore often remained at the tip of the upper tuyere, and the injection of ore was interrupted each time.

In the end, in order to stably inject ore, it was necessary to lower the ore injection speed compared to (a).

This will reduce metal production efficiency.

The table shows an example of manufacturing metal by injecting chromium ore, and the metal composition (A) has a higher Cr content.

Also, in terms of blowing speed (production volume), (A) is about 40% faster.
The number is increasing.

According to this table, installing the upper tuyere within the area defined by the present invention allows the ore injected from the upper tuyere to descend smoothly toward the tip of the lower tuyere, thereby improving metal production efficiency. It turns out that it is particularly effective.

[Brief Description of the Drawings] Fig. 1 is a schematic vertical cross-sectional view of a molten metal manufacturing furnace for explaining the present invention, and Fig. 2 shows an inverted conical shape necessary for smoothly descending ore. 2 is a chart showing the relationship between the maximum apex angle θ of the body and the coke particle size used. 1... Filled bed of carbon-based solid reducing agent, 2...
... Molten metal manufacturing furnace, total ... Lower row, 4 ...
... area (inverted cone), 5... area boundary line, 6... upper tuyere, 7... blowing pipe, 8
・・・・・・Peeking JL 9・・・・・・Plumb line with the top point of the lower tuyere as its apex.

Claims (1)

[Scope of Claims] 1. A packed bed of a carbon-based solid reducing agent is formed, and a plurality of slats are provided in two upper and lower stages in the lower part, and powder or granule ore is transported together with high-temperature air from at least the upper slats. In a vertical furnace for producing molten metal from powder ore, the shaft is axially fixed at an apex angle of θ with the top point of the lower tuyere as its apex. A vertical type, characterized in that the upper tuyere is installed at a position where the lower tip of the upper tuyere corresponding to the lower tuyere satisfies the following formula within a region where the upper tuyere forms a vertical inverted cone. molten metal manufacturing furnace. θ≦0.64X Blood+50 Where, θ: Apex angle (degrees) da: Maximum particle size (mm) of the carbon-based solid reducing agent used