JPS5918351B2 - Blast furnace wall structure - Google Patents

Description

[Detailed description of the invention] The present invention relates to a furnace wall structure of a blast furnace.

The refractories at the bottom of the blast furnace shaft are affected by the fact that the alkali contained in the blast furnace charging material accumulates inside the furnace, and this alkali and refractories react, causing alkali bursting, causing the refractories to expand, and This reduces the strength of the target and causes wear and tear.

For example, alumina-silica refractories react with alkali and produce leucite (K20, A1203.4 S
t 02 ), calcilite (K20 = A1120
3,2 S t 02 ), etc.

These facts are also clear from the dismantling investigation of blast furnaces.

Therefore, in researching refractories for the lower part of blast furnace shafts, researchers are focusing on improving their alkali resistance under reducing atmospheres.

As a result of these studies, the use of high-alumina bricks, which are more alkali-resistant, has recently become commonplace for the refractories in the lower part of blast furnace shafts, instead of the conventional chamotte bricks.

However, despite the research of many researchers, there are currently no sufficient countermeasures, and the lifespan of a blast furnace is only about 6 to 7 years, with the refractory at the bottom of the shaft still being the rate-limiting factor in many cases.

In recent years, there has been a strong demand for improvements in the alkali resistance of refractories in the lower part of the shaft due to the need to minimize blast furnace construction or renovation, which requires a huge capital investment.

As a result of intensive research into improving the alkali resistance of blast furnace refractories, the present inventors have found that alkali resistance can be significantly improved by impregnating an alumina-silica refractory with silica sol.

The present invention was made based on this fact, and the gist thereof is to use a high alumina and/or chamotite refractory whose pores are impregnated with silica sol as the furnace wall of a blast furnace, particularly the furnace wall at the lower part of the shaft.

Generally, alkaline attack on refractories penetrates into the interior through the surface and pores of the refractory and reacts with the refractory, but the present invention reduces the porosity of the refractory at the same time by impregnating the inside of the pores with silica sol. It has the effect of coating silica within the pore walls.

When this silica reacts with an alkali, it produces glass, becomes alkali-resistant with a low expansion coefficient, and prevents alkali from penetrating into the refractory structure, exhibiting excellent alkali resistance.

The silica sol impregnation-resistant person of the present invention is shown in FIG. 2A.

May be used in single layer as shown or in composite layer with other bricks.

In other words, a cooling box 2 located inside a steel shell 1 in FIG.
Silica sol impregnated alumina-silica refractory 4
Furthermore, the structure of the furnace wall lined with chamots bricks 5 is shown.

Next, examples of the present invention will be described.

The silica sol shown in Table 2 was applied to the high alumina bricks and chamots bricks shown in Table 1 using the liquid impregnation method.
It was impregnated with water.

These refractory bricks were lined at the bottom of the shaft as shown in FIG. 2A, and compared with conventional high alumina bricks and chamotite bricks that were not impregnated with silica sol.

The results are shown in FIG.

As is clear from this figure, the alumina-silica refractories that are not impregnated with silica sol (high alumina bricks A1 and chamots bricks B) expand rapidly after 12 months of operation, and after 15 months, the expansion rate reaches well over 9 to 10. In contrast, the alumina-silica refractory impregnated with silica sol (high alumina brick A', chamots brick B') has an expansion rate of only 1 to 1 even after 15 months of operation. It is about .5%.

As described above, the refractory of the present invention has less alkali attack and therefore the wear rate has been drastically reduced.

[Brief explanation of the drawing]

FIG. 1 is a graph showing changes over time in the expansion coefficients of the alumina-silica refractories of the present invention and conventional alumina-silica refractories, and FIG. 2 A shows the furnace wall structure of the present invention. 1...Blast furnace shell, 2...Cooling box, 3.
...-Cooling plate, 4... Silica sol-impregnated alumina-silica brick, 5... Chamots brick.

Claims (1)

[Claims] 1. A blast furnace wall structure in which a high alumina and/or chamots refractory whose pores are impregnated with silica sol is used in the lower part of the shaft and its surrounding area where alkali bursting is likely to occur.