JPS62116712A - Melting and smelting vessel having splash lance - Google Patents

Abstract

PURPOSE:To improve secondary combustion efficiency even if the molten slag and molten metal in an oxygen top blown converter having bottom tuyeres fluctuate by freely vertically movably provided plural pieces of splash lances in addition to a main lance for oxygen blowing to said converter. CONSTITUTION:The plural splash lances 10 are freely vertically movably attached around the oxygen feed lance 3 to the converter 1 having the oxygen feed lance 3 made into the double construction having a passage for oxygen, coke powder, etc., and passage for oxygen for secondary combustion and having the tuyeres 4 for charging the powder of raw material ore and carbonaceous material as well as Ar, O2, process gas, etc., in the stage of charging molten iron, Cr iron, etc., into the converter and producing a molten steel and high-Cr steel by oxygen blowing. Oxidizing gas, Ar, N2, process gas, etc., are blown from such splash lances 10 into the converter to splash the molten slag 5 if said slag is too large in amt., by which the secondary combustion heat generated by the oxidation decarburization refining of the molten metal 2 in the space above the molten slag 5 is effectively transferred to the molten metal 2 and the combustion heat of CO is efficiently utilized.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a melting and smelting process having a splash lance that is applied in carrying out an iron smelting reduction method, a Cr-containing hot metal production method, and a scrap melting method. It concerns containers.

[Conventional technology]

Conventionally, in the oxygen top-blown converter etc. in the smelting process, a lance is used to blow oxygen to cause the main reaction inside the furnace.
Alternatively, a lance or tuyere for blowing oxygen for secondary combustion may be provided in addition to the tuyere.
Some converters, such as the one described in No. 35764, are equipped with movable tuyeres on the side walls. This conventional technology detects carbon monoxide (CO) generated in the molten metal that rises in the slag above the molten metal and accumulates as a layer (zone) above the slag layer, and then uses the detected carbon monoxide as a reference. The side panels are moved horizontally or back and forth, and oxygen is blown through the tuyeres to completely burn out the carbon monoxide. Therefore, above the slag layer, high heat is generated due to the combustion of carbon oxide,
A slag layer exists between the molten metal surface and the high-temperature area, and since the slag layer contains air, high heat is difficult to conduct to the molten metal.

In addition to the prior art described above, there is a method in which a hole for blowing oxygen for secondary combustion is separately provided in the same lance as an oxygen blowing lance for smelting, and oxygen for secondary combustion is blown through the hole. However, in this case, the secondary combustion area is limited to the tip of the lance hole, and the secondary combustion efficiency is low.

[Problem that the invention attempts to solve]

By the way, for example, when manufacturing molten stainless steel,
Cr ore and carbonaceous material are charged into molten metal, but in this case,
Unlike the case of iron manufacturing mentioned above, a large amount of slag is produced. For example, in the above example, about 180 kg of slag is produced to produce 1 ton of hot metal, whereas about 300 kg of slag is produced per ton in the case of Cr ore reduction.

Moreover, this slag contains about 2% of unreacted Cr2O3, and it is not desirable from a cost standpoint to continuously drain and dispose of this slag. Therefore, in the reduction method for Cr ore, the operation has to be carried out in batches, and in this case, in order to properly scatter slag droplets against the constantly increasing slag, it is necessary to adjust the height of the slats. becomes.

[Means for solving problems]

The melting/smelting vessel having a splash lance according to the present invention has one or more splash lances movably installed in the furnace body in addition to the known oxygen supply lance.

[For production]

In the present invention, when producing, for example, Cr molten ore by the smelting reduction method, one or more splash lances installed in the furnace body move up and down depending on the level of slag or molten metal to generate slag droplets. Since the molten metal and slag are scattered, a certain amount of molten metal and slag can be maintained at all times.

〔Example〕

Examples of the present invention will be described below.

Figure 1 is a schematic diagram of the melting and smelting vessel of this example.
FIG. 2 is a sectional view taken along line I--I in FIG. 1. In the figure, (1) is the furnace body of the melting/smelting vessel, and in order to decarburize and refine the molten metal (2), the oxygen supply lance (1) that sprays oxygen onto the surface of the molten metal (2) 3) is inserted into the center of the furnace from the top of the furnace. Iron ore and carbonaceous materials (coal-based solid carbon materials such as coal and coke) are fed into the molten metal (2) through argon and oxygen through the raw material charging ports (4) provided at the bottom of the furnace body (1). , or continuously blown in together with process gas, etc.

Furthermore, a splash lance (1
0) are movably attached in the direction of arrow a. In the case of Figure 1, there are three Subra Sosurans (
10) is provided to move up and down parallel to the oxygen supply lance (3), and is arranged point-symmetrically with the oxygen supply lance (3) as the center, as shown in FIG. The case in Fig. 3 is the same as the case in Fig. 1, except that the splash lance (1o) is attached to the side wall of the furnace body (1) so as to move at an angle with respect to the oxygen supply lance (3). It is.

The gas blown from this splash lance (10) is an oxidizing gas (referring to a gas containing only oxygen or a gas partially containing oxygen), a process gas generated and recovered in the process, or Ar, N2, etc. Any inert gas may be used.

Although not shown, the oxygen supply lance (3) is constructed as a so-called double flow type, with a double pipe structure having a passage for blowing oxygen, coal or coke into it and a passage for blowing oxygen for secondary combustion. It has become. Furthermore, a cooling water passage is provided at the outermost periphery. The oxygen supply lance (3) also moves up and down in the direction of the arrow.

Next, the following results were obtained using a furnace capable of storing 50 tons of molten metal.

Pretreated hot metal (C=approx. 4.0%, 5i=0.1%
, p=0.025%, S=0.010%.

Temperature: 1290°C) was supplied to the furnace body (1), and Cr ore was melted and reduced according to the specifications shown in Table 1, and 48 tons of Cr-containing
Produced hot metal.

The component of the produced Cr-containing hot metal is C=5.9%.

Cr=18.2%, molten metal temperature (1620°C).

Table 1 Per 1 ton of Cri-containing pig iron [Effects of the invention] As described above, according to the present invention, one or more splash lances are movably installed in the furnace body separately from the oxygen supply lance. Even if the slag or molten metal level in the tank fluctuates during processing, a splash lance can be used to
By effectively blowing slag droplets as a heat medium into the secondary combustion zone, it has become possible to obtain high heat transfer efficiency at a two-fire combustion efficiency OD ratio of 0.4 or higher.

CO+CO2+ H2+H20 It is.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, FIG. 2 is a sectional view taken along the line r- in FIG. 1, and FIG. 3 is a schematic configuration diagram of another embodiment. (1): Furnace body, (2): Molten metal, (3): Oxidation lance, (51: Slag, (10): Splash lance.

Claims (1)

[Claims] In a method that melts and reduces ore by adding ore and carbonaceous material while spraying oxygen from an acid lance to the molten metal, droplets of slag existing on the surface of the molten metal are generated separately from the acid lance. A melting/smelting vessel having a splash lance, characterized in that the furnace body is movably equipped with one or more splash lances for splashing.