JPS59229405A - Refractory block - Google Patents

Abstract

PURPOSE:To provide a refractory block which is easily buildable and can prevent both cracking and molten metal penetration during operation by the constitution in which a projecting part to break down during operation and an allowance of a recessed shape for absorbing thermal expansion behind said projection are provided on one side of the block. CONSTITUTION:A projecting part 22 having a suitable length l1 and a max. allowance delta for expansion is formed at one end face 15 which heats up to a high temp. during operation of a blast furnace with a carbonaceous block 14 to be used for building a refractory layer in the hearth of the blast furnace. An allowance 17 of a recessed shape for absorbing thermal expansion decreasing gradually from the other surface 16 where the temp. is low to the position of the length l2 which is about <=(1/3-1/4) of the overall length L of the block 14 is provided behind said projecting part. The block 14 can be exactly and efficiently built by matching the faces of the length l2. The projecting part 22 is broken down by the expansion when the blast furnace operates then the side face 18 in the central part expands to contact tightly with the side face of the other block (not shown in figure) thereby preventing both cracking and molten metal penetration.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a refractory block used for constructing a refractory layer for a blast furnace hearth or the like.

For example, as shown in FIG. 1, a blast furnace hearth 1 has a hearth bottom refractory layer 2 having a height of 2,500 to 5,000 rrrm.
, a hearth part refractory layer 6 consisting of a hearth wall refractory layer 3 having a thickness L2 of 800 to 2800 Hn, and a furnace body cooling layer 4, for example, an iron shell having a thickness of 50 to 'i'omm whose outer surface is cooled by water spraying. , or a side wall cooling layer made of staves placed inside the steel shell, a bottom cooling layer in which air or water is passed through a duct made of steel pipes or I-shaped steel and steel plates, and a stamp layer 5 with a thickness of about 1OO1rrIn. It consists of

The blast furnace hearth section 1 is operated at 14. It stores hot metal at a temperature of 0 to 1600°C, and the refractory layer 6 is corrosion resistant.

It is constructed using a carbonaceous refractory material with excellent thermal conductivity (hereinafter abbreviated as carbonaceous block).

For example, the hearth wall refractory layer 3 is formed by stacking carbonaceous blocks in rings around the inner periphery of the stamp layer 5 in multiple stages on the hearth bottom refractory layer 2 made of carbonaceous blocks, as shown in FIG. It will be built. The carbonaceous block 7 forming the refractory layer 6 is protected by being cooled by the cooling layer 4 on its outer periphery via the stamp layer 5. The above carbonaceous block is 1
At 500°C, an elongation due to thermal expansion of 0.5 to 0.6% occurs. The above thermal expansion is absorbed in the horizontal direction of the refractory layer 6 arranged vertically. For example, vertical expansion absorption of the hearth wall refractory layer 3 is generally achieved without providing expansion absorption between the blocks in the vertical direction, and more specifically, by using open joints or by interposing joint materials with low expansion absorption capacity. As shown in FIG. 1, the fireproof layer 6 as a whole is provided with an expansion absorber 8 between the morning glory 9 and the shaft 11 to absorb the fire.

On the other hand, as a method to absorb the above thermal expansion in the horizontal direction, ■An expansion absorbing material is provided on the back side of the carbonaceous block.

■Install expansion absorbing material between carbonaceous blocks.

■Restricted from the outside and absorbed by plastic deformation of the carbonaceous block.

There are three methods.

However, the fire-resistant layers built using the above-mentioned thermal expansion absorption methods alone have advantages and disadvantages, and the fire-resistant layers built using them in combination also have drawbacks. For example, in the case of the hearth wall refractory layer 3, we will discuss the construction method that adopted the absorption method described in 1 and the drawbacks of the structure.
As shown in the figure, 60 to 90 carbonaceous blocks are stacked in rings in the circumferential direction of the furnace, with an expansion allowance between blocks 7, and more specifically, with open joints or with a joint material that does not have an expansion absorption capacity. And stamp layer 5 on the back of the blocker,
If almost all of the thermal expansion of the block 7 is absorbed, a temperature gradient will occur in the carbonaceous block 7 due to cooling during operation, and the amount of expansion on the back side will be greater than the amount of expansion on the operating side. is small, so when trying to absorb the expansion on the working surface side, the joint on the back side opens, and until the block 7 completes consolidation, the cooling capacity of the stamp layer 5 is small and the cooling of the carbonaceous block 7 itself is insufficient. This can lead to wear and tear on the operating surfaces and lead to hot water leaks. For this reason, generally the stamp layer 5
is made into a dense construction body to maintain sufficient cooling capacity at all times, and the thermal expansion tl of the carbonaceous block 7 is
Only a portion of the thermal expansion can be absorbed, and the remainder of the thermal expansion is absorbed by the absorption method (2). Specifically, since the blocks are externally restrained by the steel shell and the stub layer, the remainder of the thermal expansion is absorbed by the plastic deformation of the blocks 7.
As the size of the blast furnace increases, the degree of restraint increases, and cracks occur at a position of about % to % of the total length from the operating surface of the block. Of course, if the building is built so that all of the thermal expansion is absorbed by the absorption method (2), cracks will occur as well.

Next, we will discuss the construction method and the drawbacks of the structure that adopted the absorption method (■).

When building the refractory layer 6 on the inner periphery of the stamp layer 5 by stacking 60 to 90 carbonaceous blocks '7 in a ring in the direction of the furnace circumference as shown in FIG. i'-
An expansion absorbing material 12, specifically a joint material 12i having an expansion absorbing ability is interposed between 'i', and an expansion allowance for the block 7 is provided between the blocks 70 in the circumferential direction, so that almost all of the thermal expansion of the block 7 can be absorbed. If it is absorbed, cracks in the block 7 can be effectively prevented from occurring during operation. However, there is a drawback that the operating surface comes into contact with the hot metal before the carbonaceous block 7 is sufficiently expanded and the expansion absorbing material 12 is consolidated, and the hot metal is inserted into the absorbing material 12 portion. In addition, in FIG. 4, the joints in FIG. 3 are shifted in the circumferential direction halfway in the thickness direction of the refractory layer 6.

Furthermore, when providing expansion absorption between the blocks 7 as described above on the left, pre-lining or Protective bricks 13 may be installed, but the peeling of the bricks 13 or the intrusion of hot metal from the joints of the bricks 13 are not decisive factors in preventing hot metal intrusion, and the construction time and lead to increased costs.

As mentioned above, there are advantages and disadvantages to the construction methods and structures that employ the carbonaceous block horizontal thermal expansion absorption methods ①, ②, and ① alone, and the advantages of the construction methods and structures that adopt each of the above-mentioned absorption methods. In order to eliminate the drawbacks while taking advantage of this, a construction method has been attempted in which the absorption of thermal expansion of carbonaceous blocks is shared among the absorption methods of ■, ■, and ■ when constructing fireproof walls. The optimal distribution ratio that eliminates both generation and expansion has not been found, and in reality, the structure is constructed in such a way that z~% of the theoretical expansion amount is absorbed by the method of ■ and/or ■, and the remainder is absorbed by the method of ■. Currently, there are problems with hot metal penetration and cracking. In addition, the combination of the above-mentioned absorption methods 0,
The problem of cracks occurring in carbonaceous blocks has arisen.

The present invention has been made in view of the above-mentioned circumstances, and provides a refractory block that can efficiently build a refractory layer, and can also eliminate the occurrence of cracks during operation of the refractory layer and the insertion of hot metal. .

The gist of the present invention resides in a refractory block in which a protrusion that collapses during operation is provided on one surface of the refractory block at one end, and a concave thermal expansion absorbing type is formed behind the protrusion.

The present invention will be specifically explained below.

FIG. 7 is a plan view showing an example of the carbonaceous refractory block of the present invention suitable for use in constructing the hearth wall refractory layer 3 of the blast furnace hearth section l shown in FIGS. 1 and 2. be.

The carbonaceous block 14 in FIG. 7 has a length of one end surface 15 width Wl, the other end surface 16 width W2 (Wl (W2)), and thickness W1'.

A concave expansion absorption 1'7 is formed at the center of both sides of the block W' ((W f = W2') from the length tl from the plane 15 to the length 4 from the plane 16, and at the same time A protrusion 22 is formed at the end of the surface 15.

In the expansion-absorption type 17, the maximum expansion allowance δ at a length l from the surface 15 that becomes high temperature during blast furnace operation gradually decreases to a length t2 from the surface 16 that becomes low temperature during blast furnace operation. The length 12 depends on the amount of expansion to be absorbed by letting it escape to the back surface, but is preferably between % and % of the length L of the protrusion 14. This length t
If 2 is too large, there will be a large amount of leakage to the back, leading to openings on the back. In addition, the fourth section facilitates alignment between blocks during construction of the fireproof layer, increasing construction efficiency. Projection length t
l and the maximum expansion allowance δ formed by the protrusion are determined in relation to each other, but basically, in the thermal expansion process from the start of operation after construction to steady stable operation,
A protrusion formed on the high-temperature surface side of the carbonaceous block 14 or a block protrusion after the stage when the expansion-absorption type 17 disappears, in other words, after the stage when the side surfaces 18 at the longitudinal center of the carbonaceous block 14 are in close contact with each other. Physical properties of the block (expansion amount) so that 1° part of the length is crushed.

This is determined by taking into account the compressive strength, etc.), the restraining force acting on the block 14, and the like.

When filling the expansion-absorbing type 17 formed in the center of the carbonaceous block with an expansion-absorbing material, the expansion allowance δ is determined by considering the shrinkage characteristics of the expansion-absorbing material, and determining the length of the protrusion 8--the length of the protrusion it part. It is necessary to determine that the expansion absorbing material is consolidated by the time it collapses. length 1. The length 11 of the protrusion or block protrusion part is a shortened formula of the effective length of the block 14 which is destined to be crushed after the side surface 18 of the block 14 is brought into close contact with the block 14, so the length 2+ is the length 11 of the block protrusion part. It is preferable to keep it to the minimum necessary to effectively prevent insertion of hot metal up to the point of close contact, and 10 to 50 times is preferable.

The carbonaceous block 14 of Fig. 7, in which the length, width, Wl, W2 + thickness, w, length 11.12, and expansion allowance δ have been determined as above, is constructed as shown in Fig. 9-a. By stacking rings as shown in FIG. 8 on the refractory layer 2 at the bottom of the hearth, and forming a plurality of rings as shown in FIG. There is no expansion allowance at both the side and back ends, and the center part gradually decreases from the operating surface side to the back side, and after operation, it disappears by the time the operating surface side end collapses. The blast furnace hearth wall refractory layer 3 having the structure shown in FIG. 13) is constructed.

How can the blast furnace hearth wall refractory layer 3 be constructed using the carbonaceous block 14 of the present invention without providing an expansion allowance at both ends of the working surface side and the back side between the carbonaceous blocks 14 in the circumferential direction? In the center part, there is an expansion and absorption allowance that gradually decreases from the operating surface side to the rear side and disappears by the time the operating surface side end collapses after operation, so from the start of operation after construction to steady operation. Thermal expansion of the working surface side end of the carbonaceous block up to the end is effectively used for plastic deformation and close contact between the upper and lower ends of the side spools, and the insertion of hot metal into the expansion allowance at the center of the block is effectively used. On the other hand, the thermal expansion that gradually decreases from the operating surface side to the back side of the central part of the carbonaceous block until steady operation does not cause cracks to occur in the central part of the block.
It is effectively used to eliminate the expansion allowance in the center part and bring the side faces of the center part of the carbonaceous block into close contact with each other. In this case, the protruding part of the block is crushed, but at this time, as mentioned above, the sides of the central part of the block are in close contact with each other, or are in close contact due to plastic deformation, so it is possible to effectively prevent the insertion of hot metal from this point onwards. It is. When building the refractory layer 3 of the blast furnace hearth wall, a carbonaceous block having a protrusion and an expansion absorption layer formed on only one side can be used to effectively prevent cracks from occurring and penetration of hot metal.

Fig. 9-b shows that a carbonaceous block 14'' with an expansion allowance δ provided on the lower surface and both circumferential sides of the lower layer of the hearth wall refractory layer 3 of Fig. 9-a is used, and the upper layer is This shows an example of construction using a block 14' in which an expansion allowance δ is provided on the upper and lower surfaces of the carbonaceous block 14 shown in FIG. There is no need to provide an absorption type 8.

Figure 9-a shows an example in which the refractory block of the present invention is used during the construction of the hearth bottom refractory layer 2 before constructing the hearth wall refractory layer 3 in Figure 9-b. In the hearth bottom refractory layer 2 of this example, the outer periphery is constructed by stacking carbonaceous blocks in multiple stages of rings, the lower center layer is constructed by stacking carbonaceous blocks vertically, and the upper layer in the center is built on top of the lower layer. It is constructed by placing carbonaceous blocks on the outer periphery, and the third (and fourth) tier of the outer periphery uses blocks 14" with an expansion allowance δ on only the upper surface (and only the lower surface). As shown in FIG. 11, which is a view taken along arrow A-A in FIG. 9-a, there is an expansion allowance δ on the four sides.
The upper layer of the central part is also constructed using block 11'' with expansion allowance δ on four sides.

The central lower layer is a block 14 with an expansion allowance δ on two sides.
Of course, the same applies to the upper layer of the central part. Fig. 8 shows a view taken along the arrow B-B of Fig. .

As is clear from the above construction examples, the 11° angle shown in Fig. 7 is applied to one side, or two other sides, or the other three sides, or the other four sides, excluding the high-temperature surface and the low-temperature surface. t
By using the refractory block of the present invention in which the refractory blocks 2 and δ are provided, an expansion allowance is not provided at both ends of the diblock horizontally and/or vertically, but an expansion allowance is provided at the center. A layer is formed to effectively prevent the occurrence of cracks and the penetration of hot metal.

Examples of the present invention will be specifically shown below.

As shown in FIGS. 12 to 14, the carbonaceous block 14 according to the present invention shown in FIG. 15 was constructed in the lower stage, and the comparative carbonaceous block 21 shown in FIG. 16 was constructed in the upper stage, and an experiment was carried out. The operation was carried out.

During construction, the part according to the present invention allows the expansion of the carbonaceous blocks by 6o'X) between the carbonaceous blocks.

The stamp material 5 on the back side absorbs 30%, and the rest can be absorbed by the elastic deformation of the carbonaceous block. As shown in FIG. 13, one half of the block was provided with a carbon-based absorbent material 19 in the expansion absorption part of the block, and the other half was set to δ-0, 7wn, and the other half was expanded to 6 gates as expansion absorption 20.

In the comparative part, the back stamp absorbs 30%, and an expansion absorbing material that absorbs about 10% of the expansion was provided between the carbonaceous blocks.

Preheat the furnace body to 1200℃ in a reducing atmosphere and heat it to 1200℃.
As a result of heating the block 21 to 1550° C. and maintaining it for 10 days, cracks occurred in the comparative block 21 at a distance of % to % of the length of the block from the operating surface.

There was no insertion of hot metal into the furnace part according to the present invention, and although the working surface part (cAa in Fig. 15) of the carbonaceous block 14 according to the present invention was crushed, no other cracks occurred. , good results were obtained.

As described above in detail, according to the refractory block of the present invention, the refractory layer can be constructed efficiently, and when the refractory layer is operated,
It is possible to effectively prevent the occurrence of cracks due to molten metal pouring, and the life of the refractory layer can be effectively extended.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the structure of the blast furnace from the lower shaft to the hearth.
Figure 2 is an explanatory diagram of a horizontal cross section of the blast furnace hearth wall, Figures 3, 4, 5, and 6 are explanatory diagrams of an example of setting an expansion allowance.
The figure is an explanatory diagram of an example of a carbonaceous refractory block according to the present invention, and Figures 8, 9-a, 9-b, 9-0, 10, and 11 are in accordance with the present invention. Fig. 12 is an explanatory diagram of the construction status of the blast furnace hearth section constructed using refractory blocks related to
Figures 13 and 14 are explanatory diagrams of the construction status of the experimental reactor, Figure 12 is an explanatory diagram of the horizontal cross section of the D-D section shown in Figure 14, and Figure 13 is the illustration of the C-D section shown in Figure 14. Figure 14 is an explanatory diagram of a horizontal cross section of the -0 part, Figure 14 is an explanatory diagram of a vertical cross section of the experimental reactor, Figure 15 is an explanatory diagram of the carbonaceous refractory block according to the present invention used in the experiment, and Figure 16 is an explanatory diagram of the experimental reactor. FIG. 3 is an explanatory diagram of a comparative carbonaceous block used in the above. 15-1...・Blast furnace hearth section 2...Blast furnace hearth bottom refractory layer 3...Blast furnace hearth wall section large-scale layer 4...Furnace body cooling layer 5... Stamp layer 6... Hearth part refractory layer 7... Carbonaceous block 8... Expansion absorption 9... Morning glory 10... ...Furnace belly 11...Shaft 12...Expansion absorbing material 13...Brick for front covering or protection 14°...
・Carbonaceous block 15... Surface 16 of the carbonaceous block that has cylinder temperature...
...Low temperature surface 17 of carbonaceous block...1 day of expansion and absorption...Central side surface 16-19...-Expansion and absorption filled with expansion absorbing material 20... ...Expansion and absorption that disappears before the high-temperature side end collapses after operation 21 ... Carbonaceous block for comparison 22 ... Protrusion Applicant Nippon Steel Corporation Figure 1 Figure 2 Figure 3 Year 414-Takumizu

So: >6”)”. Figure 10 Figure 1... 14゛, :m knee 1':E, 21----------- 1-j--1------ 1211!1 Rod 14 figure

Claims (1)

[Claims] A refractory block that has a protrusion that collapses during operation on one side of the refractory block at one end, and a concave thermal expansion absorption type formed behind the protrusion.