JPS626115Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention relates to a smelting furnace with a bottom blowing function.
In particular, the aim is to effectively extend the life of the refractories.

Here, the smelting furnace with bottom blowing function is Q.
-Bottom-blowing converters, typically the Bop process, and the simplified K-Bop process, in which a top-blowing lance is added, are representative examples, as well as bottom-blowing converters, as well as blowing in these converters. A tuyere similar to a tuyere is installed through a refractory wall surrounded by an iron shell, and a gas for refining or at least stirring is supplied to the molten metal bath contained and maintained in the internal space of the wall. The above-mentioned blowing tuyeres are also used for so-called out-of-furnace refining ladles and other containers in which blowing is carried out.
It shall be broadly inclusive as long as it has more than one.

In refining operations by blowing the above gas through such blowing tuyeres, as shown in the typical example of the K-Bop method below, even though the refractory lining bricks still have sufficient residual thickness, It has been experienced that the paint falls off prematurely, and that gas is often released at the spray repair site, resulting in delamination.

Therefore, the inventors investigated the cause of the difference in the remaining thickness when the refractory lining brick fell off, and measured the pressure in the pores on the back side of the refractory lining brick inside the steel shell. It has been found that the higher the pressure, the greater the residual thickness, and that when the pressure is close to normal pressure, no shedding occurs until the final life thickness is reached.

After careful consideration of such behavior, the furnace body of the above-mentioned K-Bop converter generally has 2 permanent bricks on the inner periphery of the furnace shell 1 that surrounds it, as shown in Figure 1.
Refractory peripheral wall 4 lined with movable bricks 3 through
And on the bottom shell 5, which is normally removable from the bottom opening, there is a permanent brick 6 in almost the same way as above.
Refractory bottom wall 8 lined with working bricks 7 through
A so-called double-pipe tuyere 9, which penetrates the hearth shell 5 and the refractory bottom wall 8 and opens into the furnace, is provided, near the outer periphery of the end of the tuyere.
As shown in Fig. 2, tuyere protection is released to surround the oxygen gas stream blown into the molten metal bath 12 from the inner tube 11 through the circumferential gap 10 in the inner and outer tubes of the double tuyere 9. For example, a so-called pine room 12 is formed by the cooling effect of a gas stream of a hydrocarbon gas such as propane.

Due to the development of the mash room 12, the flow resistance in the porous pores increases, and the tuyere protection gas
It was discovered that the air passes through the gaps between the working bricks 7 on the outer periphery of the outer tube 13, and as shown by the arrows 14 in FIG. 2, penetrates into the small gaps facing the hearth shell 5 and the shell 1 on the back side of the refractory bottom wall 8 and the circumferential refractory wall 4, and is trapped there, where the pressure increases under the action of the static pressure of the molten metal.

Therefore, this invention makes it possible to extend the life of refractories in this type of smelting furnace by providing a means for advantageously dissipating the gases trapped in the above manner.

This gas dissipation is achieved by forming an opening 15 in the furnace shell at an appropriate position according to the structure of the furnace body and the construction procedure of the refractory, and communicating with the gap on the back side of the lining, so as not to damage the strength of the furnace body. Of course, if necessary, it is also possible to provide reinforcement for the opening, and usually there are 2 to 4 holes on the circumference just below the trunnion ring 16 as shown in FIG. The purpose of this idea is met to a certain degree.

In the example of the K-Bop converter shown in Figure 1, one opening of 50 mmφ is placed on the diameter of the furnace body on the trunnion side.
As a result, the pressure inside the pores on the back side of the lining of the furnace shell, which was conventionally about 2.0 atm, decreased to 1.2 atm.
The remaining thickness of the refractory that fell out due to the drop in atmospheric pressure was previously as high as 120 mm.
It has been drastically reduced to about 40mm, which has fully fulfilled its durability life.

Incidentally, the relationship between the remaining time of the refractory repair material depending on the above-mentioned pore pressure, that is, the time the sprayed repair material can withstand during blowing without chipping away, is also shown in Figure 3 as an example. It almost doubled.

As described above, according to this invention, it is possible to effectively avoid premature damage to refractories in a smelting furnace with a bottom-blowing function, and to almost complete the life of the refractories. The frequency of repairs such as flaking of the sprayed repair material can be advantageously reduced, thereby significantly contributing to improving the operating efficiency of the refining furnace.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a refining furnace with a bottom-blowing function, Figure 2 is a detailed view of the double tuyeres at the bottom of the furnace, and Figure 3 shows the pore pressure behind the refractory and the remaining repair material. This is a correlation graph with time. 1... Furnace body shell, 4, 8... Lining refractory, 1
5...Opening.

Claims (1)

[Scope of utility model registration request] A smelting furnace with a bottom-blowing function, which has an opening in the furnace body shell that communicates with a gap on the back side of the lining of the steel shell.