JPS6280213A - Method and apparatus for applying heat to molten metal in smelting furnace - Google Patents

Abstract

PURPOSE:To apply a large quantity of heat to a molten metal and to make efficient smelting of a molten iron by obliquely blowing an oxidizing gas to the slag generated in the molten metal to burn the gaseous CO floating in the slag and swirling the slag. CONSTITUTION:The iron oxide ore and coal are charged into the smelting furnace 1 and are heated to melt. An O2 jet is further blown into the molten metal 5 from the above-mentioned tuyere 3 to stir the molten metal 5. The iron oxide is thus reduced by the coal and CO is formed. The gaseous CO is floated on the slag layer 4 in the upper layer through the molten metal 5. The gaseous CO floating on the above-mentioned slag 4 is burned by the oxidizing gas such as O2 blown from tuyeres 2-2e for secondary combustion bored to the side wall 1 of the smelting furnace. The heated slag 4 is thereby swirled and the heat is efficiently applied to the molten metal 5. Plural pieces of the above-mentioned tuyeres 2- are provided and the angle theta of inclination on the plane with the furnace center is adequately determined at 0<theta<90 deg.-180 deg./n (number of the tuyeres 2; n;>=3) or 0<theta<45 deg. (n; 2).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for adding heat to molten metal in a smelting furnace such as a direct smelting reduction furnace and a converter.

[Conventional technology]

Conventionally, in an oxygen top-blown converter etc. in a smelting process, a lance or tuyere is provided to blow oxygen for secondary combustion in addition to a lance or tuyere for blowing oxygen to cause the main reaction in the furnace. For example, there are converters such as the J converter described in Japanese Patent Publication No. 53-35764 that have movable tuyere mounted on the side wall. This conventional technology detects carbon oxide (CO) generated within the molten metal, which rises in the slag above the molten metal and becomes trapped as a slag (zone), and uses the detected carbon monoxide as a reference. Move the tuyere on side i horizontally or back and forth and blow in oxygen from one tuyere to completely burn out the carbon monoxide.

Therefore, above the slag layer, high heat occurs due to the combustion of carbon oxide, but there is a slag layer between the hot water surface and the high temperature area, and the slag layer contains air, so high heat does not occur. Difficult to conduct to molten metal.

In addition to the above-mentioned conventional techniques, there is a method in which the same lance as the oxygen injection lance for smelting is provided with another hole, and the oxygen for secondary combustion is blown through the hole. However, in this case, the area of secondary combustion is limited to the tip of the lance hole,
Secondary combustion efficiency is low.

[Problem that the invention seeks to solve]

In a converter equipped with a secondary combustion lance or tuyere as described above, oxygen from the secondary combustion lance or tuyere is blown into a specific position within the molten metal or into the carbon monoxide layer above the slag. Therefore, there was a problem in that it was not possible to add all of the high heat generated by the secondary combustion to the molten metal.

[Means for solving problems]

Regarding this invention! The method of adding heat to the molten metal in a JI smelting furnace is to inject oxidizing gas into the slag layer at an angle, and burn the carbon monoxide floating in the slag in the slag layer. The slag layer is added to the hot molten metal by swirling and circulating the layer.

Further, in the device according to this other invention, a plurality of secondary combustion tuyeres are provided at the position of the slag layer above the hot water surface of the side wall, and the number of secondary combustion tuyeres is n b'-n 〉3 In this case, the angle θ connecting the core and the installation point on the plane is 0〈θ〈9σ−1
80', and if the number n is 2, then θ〈4
It is disposed within a range of 5° and is also inclined in the vertical direction.

[Effect]

In this invention, the slag layer, which has become significantly hotter than the temperature of the molten metal due to the combustion of carbon oxide, is swirled and circulated by the acidic gas flow for secondary combustion and the CO gas flow generated by the CO combustion, so that a heat flow is generated. It faces toward the molten metal, allowing effective heat transfer from the slag to the molten metal.

In this other invention, the acidic gas for secondary combustion is blown into the slag layer from the tuyere which is inclined in the same circumferential direction of the furnace side wall in a certain plane plane and is also inclined in the vertical direction. - The carbon oxide can be burned and the slag bed can be turned into a swirling and circulating flow.

〔Example〕

FIG. 1 is a plan cross-sectional view of a smelting furnace in which the method of the present invention is carried out. In the figure, (1) is the furnace wall of the smelting furnace, (2) to (
2e) is a tuyere for secondary combustion arranged on the furnace wall.

゛(3) is a tuyere for blowing oxygen powder for bottom blowing. Tuyere (
2) □ to (2e) are arranged to be inclined at a predetermined angle in the horizontal and upper F directions, and the horizontal inclination angle θ is determined by the relative relationship with the number of tuyeres, and the number of tuyere is 5 n. Then, when n > 3, the angle satisfies the following equation, and when the number of tuyeres is n = 2, the angle satisfies the following equation.

0<θ<45°...(2)", which is the angle to the line connecting the installation point and the reactor core.

Mi;,, yo, the above (, n, formula (2). Range slope 'gFL
, C, but 1 All tuyeres (2) to (2e) do not need to be at the same angle □, but each angle of tuyere (2) to (2e) can be calculated using the above equation (υ, (2)) The angles of some of the tuyeres (2) to (2e) may be changed within the range of Although they are not thrown, they may be tilted vertically alternately, or a predetermined number of stitches (2) to (2e) may be grouped and tilted vertically.

The tuyeres (2) to (2e) are provided at positions where a slag layer is formed on the furnace wall of the smelting furnace. The molten metal in the smelting furnace is more fluid due to the oxygen jet for blowing or the blowing of powder and gas during melt reduction, but the height of the molten metal surface and the thickness of the slag layer above it are within a certain range. Therefore, the tuyeres (2) to (2e) may be arranged in that range.

In ironmaking by direct smelting reduction or steelmaking by oxygen bottom blowing in the smelting furnace configured as described above, the following method is used to add the combustion heat of carbon monoxide in the slag layer to the molten metal.

In ironmaking by direct smelting reduction, the smelting furnace shown in Figure 1 (hereinafter referred to as smelting furnace refers to the one shown in Figure 1)
Powdered iron ore as iron oxide and coal as powdered solid reduction 41 are charged through the tuyere (3) and heated and melted. And in the same way, oxygen is collected from the inner tube of the bottom panel (3) of the smelting furnace.

As a result, the molten metal is stirred by oxygen (diene) K and flows, iron oxide (Fe20s) undergoes a reduction reaction with the carbon (C) of the coal, and the produced monocarbon (CO) floats up in the molten metal. It passes through the slag layer and rises to the top of the furnace. Therefore, through the tuyeres (2) to (2e), oxygen for incomplete combustion or an oxidizing gas such as a gas containing oxygen is injected into the slag layer to burn the carbon monoxide (CO) in the slag layer. Bring the slag layer to a high temperature.

On the other hand, the oxygen for secondary combustion or the gas containing oxygen is
Since the slag layer is blown in from the tuyeres (2) to (2e) inclined in the circumferential direction of 1), the slag layer forms a swirling circulation flow within the furnace. Moreover, this swirling circulation flow not only swirls on a plane;
It can also rotate up and down and diagonally.

The contact area between the molten metal surface and the slag layer is small,
The state becomes more dynamic, and the high heat in the slag layer is efficiently conducted to the molten metal.

Also, in oxygen bottom-blown smelting, P sintering heat of carbon monoxide (CO) can be efficiently added to the molten metal by a similar operation.

FIG. 2 is a side sectional view of the smelting furnace shown in FIG. 1, in which oxygen for secondary combustion or oxygen is contained in the slag layer (4) from the tuyeres (2) to (2e) for secondary combustion. This figure shows the state in which gas is blown into the slag layer (4), which becomes extremely hot, and circulates through the car to add heat to the molten metal (4).

〔Effect of the invention〕

As explained above, in this invention, the heat of combustion of carbon monoxide generated in the slag layer is added to the molten metal through the swirling of the slag layer, thereby reducing the reaction in direct smelting reduction steelmaking, which requires a large amount of heat. Efficiency b' - In addition to being able to perform sealing 1 using a converter, thermal efficiency can be increased, which is effective.

In addition, this other invention provides a plurality of secondary combustion tuyeres that are inclined within a certain range at the position of the slag layer on the side wall of the smelting furnace, so that the slag layer can be efficiently (swirled). There is an effect that can be done

[Brief explanation of drawings]

FIG. 1 is a plan sectional view showing an embodiment of the present invention, and FIG. 2 is a side sectional view thereof. In the figure, (1) is the side wall of the smelting furnace, (2) to (2e)
is a tuyere for secondary combustion,
4) is a slag layer, and (5) is a molten metal. Agent Patent Attorney Tadashi Sato Year 1 Figure 2d 2-2e

Claims (2)

[Claims] (1) The carbon monoxide gas generated in the molten metal in the smelting furnace and floating in the slag is combusted by injecting oxidizing gas into the slag at an angle, and the slag, which burns and heats up, is swirled. , a method for adding heat to molten metal in a smelting furnace, characterized by adding heat from slag to molten metal. (2) In a smelting furnace, a plurality of secondary combustion tuyeres are provided at the position of the slag above the hot water surface of the side wall, and the secondary combustion tuyere is placed on a plane when the number n is n≧3. If the angle θ with respect to the line connecting the core and the installation point is 0<θ<90°−180
If the range n is 2, then 0<θ<4
A device for adding heat to molten metal in a smelting furnace, characterized in that it is arranged within a range of 5° and is also tilted in the vertical direction.