JPS61227111A - Method for sealing dust during repair of throat of blast furnace - Google Patents

Abstract

PURPOSE:To inhibit the generation of white smoke from a blast furnace and to increase the efficiency of repair when the throat brick of the furnace is repaired by spraying, by covering the surface of the charge in the furnace with blast furnace ballast under specified conditions. CONSTITUTION:A hand sprayer 3 or an automatic sprayer 4 is put in a blast furnace from a manhole 2 by the big bell 1, and the throat brick of the furnace is repaired during the suspension of blowing. At this time, the surface of the charge 6 in the furnace is covered with blast furnace ballast 7 of 5-20mm grain size to about 500-1,500mm thickness prior to repair so as to inhibit the generation of white smoke and to carry out efficient repair by spraying.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a method for suppressing the generation of dust (white smoke) from inside the furnace that obstructs visibility during spray repair of bricks at the mouth of a blast furnace. @ (Prior art) Conventionally, the repair of bricks at the four mouths of a blast furnace was carried out mainly by using three manual spraying devices and an automatic spraying method into the furnace from the manhole 2 next to the large pel 1, as shown in Figure 2, during wind breaks. The test is carried out using the device 4. Note that 5 indicates a cooling pipe and 6 indicates a charge.

(Problem to be solved by the invention) However, with the method of the above configuration, the visibility from outside the furnace is obstructed by the generation of white smoke (dust) from inside the furnace, so it is said that sufficient spraying cannot be performed for repair. There was a problem.

Therefore, an object of the present invention is to provide a method for suppressing the generation of white smoke from inside the furnace, which is a problem with the prior art, and increasing the efficiency of brick spraying repair.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention attempted to seal the furnace mouth by putting coke or sintered ore on top of the special charging material, but the white smoke suppression effect was not achieved. There wasn't. 4The white smoke (dust) adhering to the spraying equipment was scraped off and chemical analysis was performed.
Its chemical composition was as shown in Table 1.

As a result, the components of white smoke are mixed with scale, and Fl! OX
Although 2>f is high, except for FaOx,
1 Table ZnO was high, and it was found that the main component of the white smoke was ZnO. Note that S102 and Al2O3 are also high values, but these are probably components of the spray agent, and it is thought that particles that did not adhere to the furnace wall were blown away. It was found that there was a Zn enrichment zone at the top of the sticky shaft. This was reduced in size to repair the furnace opening brick, but after the reduction, a Zn enrichment zone appeared on the surface of the charge 6. In order to prevent the generation of ZnO, which is the main component of this white smoke, the surface of the charge 60 is coated with blast furnace ballast (crushed slag) to remove the white smoke from inside the furnace. It was discovered that smoke generation can be suppressed. That is, 50% of blast furnace ballast with a particle size of 5 to 20% is placed on the charge.
The coating is made to have a thickness of about 0-1500%.

(Function) When blast furnace ballast is used in this way, the particle size is 5-20%.
It has fine grains, excellent gas sealing properties, and is well-sized, so it does not impede air permeability during blast furnace operation. In addition, the melting temperature of blast furnace ballast is around 1400℃,
It is not much different from that of sintered ore, and melting in the furnace does not change the properties. Furthermore, the heat load applied to the blast furnace is smaller than that of ores, which allows for large quantities to be used, and eliminates the generation of white smoke.
The particle size structure of the blast furnace ballast is as shown in Fig. 3.

(Example) An example of the present invention will be explained in detail below with reference to the drawings. Figure 1 is a cross-sectional view of the structure showing an example of the method of the present invention, and
Parts that are the same as in the figures are given the same reference numerals.

First, during normal operation (high pressure), the blast furnace ballast is inspected in advance in the ore tank, and the low air volume (BV3000
-500), cut it out at low pressure and charge it all at once if possible. It is more effective to push the armor (not shown) toward the center during charging so that the ballast reaches the center of the furnace. The effect is best when the layer thickness of Baras 7 is slightly thin. On the other hand, if it is too thick, it will be difficult to charge, and in addition, after repair,
◎ Therefore, based on the experimental results, it is best to set the distance within 500 to 1500X and about 1 m. In other words, if the layer thickness of the ballast is less than 500%, white smoke will occur, and if it is more than 1500X, the amount of 10 will be large.
Productivity decreases Next, the optimum grain size for one balas is 5-20%, which has excellent gas sealing properties, and because the grains are sized, it does not impede air permeability during blast furnace operation. Moreover, since ballast is susceptible to heat cracking, the longer it takes to charge, the better the sealing performance becomes. In addition, the melting temperature of blast furnace ballast is around 1400°C, which is not much different from that of sintered ore, and the melting properties in the furnace do not change. In addition, the heat load applied to the blast furnace is smaller than that of ores, and it has the advantage that it can be used in large quantities.In addition, ballast is originally a blast furnace product, and its composition is the same as that of blast furnace slag. weight t%) is 81022 t36
External Ca035~45%%Al2O38~16%%FeO
()=1%〇Also, there has been no case where spraying could not be performed due to the generation of white smoke after using the ballast, and the success rate is 100%.

(Effects of the Invention) As described above in detail, according to the present invention, when the bricks at the mouth of the blast furnace are sprayed for repair, they are covered with the charging material T-ballast, thereby suppressing the generation of white smoke from inside the furnace. It has the effect of increasing the efficiency of brick spray repair. Furthermore, it does not impede air permeability during blast furnace operation, the molten metal in the furnace does not fall off, and its properties do not change, and the heat load applied to the blast furnace is smaller than that of ores, allowing for large amounts of use.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of the method of the present invention, and FIG.
The figure is a cross-sectional view of the structure according to the conventional method, and Fig. 3 is a diagram showing the particle size structure of blast furnace ballast. Spraying device, 5... Cooling/quive, 6... Charge, 7... Noklas.

Claims (1)

[Claims] When spraying and repairing bricks at the mouth of the blast furnace, 500 to 150 particles of blast furnace ballast with a particle size of 5 to 20 m/m are placed on the charge.
A dust sealing method for repairing the mouth of a blast furnace, which is characterized by applying a coating to a thickness of about 0 m/m to suppress dust generation from inside the furnace.