JPH0499110A - Structure of refractory at shaft part in blast furnace - Google Patents

Abstract

PURPOSE:To improve durability of a shaft part in a furnace by fitting a large block, which is constituted of an SiC quality material having excellent wear resistance and spalling resistance and formed to integral structure by packing refractory in the inner part, to inner face of an iron shell through the refractory heat insulating material. CONSTITUTION:Main body block 1-1 constituting the large block is fitted to the inner face of iron shell by penetrating bolts 5 for fitting this block into bolt holes 1-3 for fitting. Successively, a cover body 1-2 is fitted by penetrating the bolts 5 for fitting into bolt holes 1-5 for fitting, and also by fastening with nuts 1-7, thus, this large block is perfectly fixed to the iron shell 1. After that, the refractory (1-8) is packed into inner part of the block from pressing-in hole 1-4 for refractory. The large blocks 1 are fitted to the iron shell from lower step in order to manufacture the furnace wall. Then, as joint in each gap between the large blocks, the fire-resisting insulating material 4 which absorbs the expansion of these blocks is packed into the gap. As the large block is made of the SiC quality material having excellent wear resistance and spalling resistance compared with the ordinary chamotte quality, or high alumina quality refractory brick, this has high durability and long service life.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a refractory structure in a blast furnace shaft, particularly in the upper part of the shaft. It relates to a refractory structure that is strong and has a long life due to its large blocks.

Conventional Technology Currently, blast furnaces undergo renovation work every 7 to 10 years, and refractory bricks suitable for each part are used on the inner surface of the blast furnace body along the iron skin of the furnace body.

The lower part of the Bosch Berry shaft of the furnace body is lined with refractory bricks on the inner surface of the furnace, and a jacket (
Generally, a cooling box) and a stave (water-cooled large block) system are adopted.

However, since the upper part of the shaft becomes supercooled, we use only refractory bricks and cut several types of bricks into rounds along the steel skin (90 to 100 mm thick x 100 to 150 mm wide x 3 lengths).
00 to 400 mm) depth 2 to 3 layers are combined, mortar is applied to the refractory bricks, and lining is carried out by stacking them one layer at a time.

On the other hand, the lower part of the blast furnace body (bosch, beam, middle and lower part of the shaft) is equipped with cooling equipment such as a cooling box and stave, so damage to the refractory is gradual, and even if the refractory is melted, the cooling box and The stave protects the furnace wall.

However, as mentioned above, the upper part of the shaft is constructed by stacking small refractory bricks like building blocks, and is not fixed to the steel shell of the furnace body. and contact/thermal change (300-8
Due to repeated spalling caused by temperatures (00℃), bricks began to fall off locally about 2 to 3 years after the start of operation after renovation work, and the surrounding brick joints gradually loosened, causing the falling off to spread throughout the area. It is a common phenomenon to go.

These phenomena affect the entire shaft section, and if left untreated, the iron skin will be exposed and at the same time gas flow will deteriorate, greatly affecting operations.

Various repair techniques have been developed to prevent these problems, but they require enormous repair costs.

In addition, various materials are being considered for the refractory bricks, but since the iron skin of the main body is sloping, especially in the upper part of the shaft, if the lower brick is damaged and falls off, the intact brick at the upper part will also be affected by its own weight. It falls off.

Therefore, it is impossible to fundamentally solve the problem even if the material of the firebrick is changed.

Recent technology involves installing water cooling boxes, staves, etc. up to the top of the shaft (previously up to the middle of the shaft), but the reality is that this leads to overcooling, which has a negative impact on operations.

Problems to be Solved by the Invention As mentioned above, the upper part of a conventional blast furnace shaft is constructed by stacking refractory bricks like building blocks, so at an early stage the brick joints become loose due to contact with ore and spalling due to thermal changes. There is a problem in that localized falling off of the bricks occurs, resulting in a decrease in the strength of the structure, and a chain reaction in which the refractory bricks fall off, necessitating huge repair costs to prevent these phenomena.

Further, even if a water-cooled box or a stave method is adopted, there is a problem of overcooling and it is not easy to implement.

In view of these circumstances, this invention provides high durability and high performance by using heat-resistant blocks made of materials with excellent wear resistance and spalling resistance, instead of the conventional brick construction method and cooling method. This paper attempts to propose a long-life blast furnace shaft refractory structure.

Means for Solving the Problems The gist of the present invention is to make the inner surfaces of the front, back, left and right side surfaces, and top and bottom surfaces of Si, which has excellent wear resistance and spalling resistance.
A large block of required thickness made of C material and filled with refractory material inside to form an integral structure is installed along the inner surface of the steel shell through fireproof insulation material, and at the joint between the blocks. The shaft part has a refractory structure filled with fireproof insulation material.

Function SiC material with excellent wear resistance and spalling resistance is
A SiC monolithic refractory is formed into a plate of a desired size and thickness, and after curing is sintered in a firing furnace at a temperature of 1000 to 1200°C to sufficiently develop strength.

The structure of a large block is, for example, divided into a main body box and a lid, both of which are made of SiC material.The main box has multiple mounting bolt holes on the bottom and refractory press-fit holes on the top, and the lid has a has a bolt hole that matches the front bolt hole;
Furthermore, a plurality of SiC asian anchors are placed on the entire inner surface, and the main body and the lid are attached integrally with bolts, and the refractory is filled through the refractory press-in hole.

When attaching a large block to a blast furnace shell, install bolts that protrude into the blast furnace shell in advance, and fix the main box to these bolts through fireproof insulation material of an appropriate thickness installed on the inner surface of the steel shell. Next, the lid is set and installed by screwing the nuts onto the bolts and tightening them, and then filling the refractory material through the press-fit holes.

The joints (horizontally and vertically) between large blocks are filled with fireproof insulation material that can absorb the expansion of the blocks.

In the refractory structure of the present invention, the large block is fixed to the steel shell, so there is no possibility of local falling off or loosening of the joints.

Since the Daisho block is made of SiC material, which has superior wear resistance and spalling resistance compared to chamots and high alumina refractory bricks, a furnace wall with high durability and long life can be obtained. Furthermore, since each large block is attached individually, even if one block is damaged or falls off, it can be repaired by simply replacing that block.

Since the furnace walls are composed of large diblocks, the construction period can be significantly shortened compared to brick masonry construction. Furthermore, since it is a dry type, significant energy savings can be achieved.

Embodiment FIG. 1 is an exploded perspective view showing an example of the structure of a large block according to the present invention, FIG. 2 is a vertical sectional view showing a part of the large block attached to the upper part of a blast furnace shaft, and FIG. It is a longitudinal cross-sectional view which expands and shows the large block same as the above.

In Figures 1 to 3, (1) is a large SiC block, (2) is a blast furnace shell, (3) and (4) is a fireproof insulation material,
(5) is a large block mounting bolt.

The large block (1) consists of a main body box (1-1) and a lid (1-2), and the main body box (1-1) has mounting bolt holes (1-3) on the bottom and on the top. Refractory material press-fit holes (1-4) are drilled in each of the holes. Lid (1-
2) has a bolt hole (1-5) that matches the bolt hole on the main body box side, and a SiC Asian anchor made of the same material on the inside.
6) is provided protrudingly.

Large block mounting bolt holes (1-3) (1-5)
The diameter is approximately 5 to 10 mm larger than the thickness of the mounting bolt (5) to facilitate construction and to prevent cracks from occurring due to bending stress etc. even if the large block (3) moves due to thermal expansion.

The size of this large block is not particularly limited, but it is usually 1,500 to 2,000 mm in length x 1 in width.
000~1500mm x thickness (including lid) 600
~700mm.

The construction method for the above large blocks is blast furnace shell (2).
Mounting bolts (5) for fixing the large block (1) to the inner surface of the furnace are provided protruding from the steel shell (1) by welding, etc., and a refractory insulation material (3) is installed on the inner surface of the steel shell with a length of 50 to 100 mm.
Construction will be carried out to some extent. It goes without saying that the block mounting bolts (5) are made of heat-resistant steel suitable for the operating temperature.

Next, the main block (1-1) that constitutes the large block
Insert the mounting bolt (5) into the mounting bolt hole (1-3).
) and attach it to the inner surface of the steel skin. Next, the lid body (1
-2) to the mounting bolt hole (1-5).
5) and install it through the nut (1-7).
Tighten to completely fix the large block to the steel shell (1).

Thereafter, the inside of the block is filled with refractory material (1-8) through the refractory material press-in hole (1-4). The fireproof material is preferably one that has high adhesive properties and hardens even at room temperature.

In this way, the furnace wall is constructed by attaching the large blocks (1) to the steel shell in sequence from the bottom. At that time, the joints between each large block are filled with a fireproof heat insulating material (4) capable of absorbing the expansion of the block.

Here, as a construction method for large blocks, we have shown a method in which the blocks are assembled one after another inside the furnace, but a method in which the large blocks are assembled in advance outside the furnace and then installed one after another on the blast furnace shell is adopted. It is also possible.

As described in detail, the refractory structure of the present invention provides the following effects.

■ Because it is constructed from large blocks without using any small firebricks and is fixed to the steel shell, it does not fall off locally like small firebricks and the surrounding area does not loosen.
It will not fall off even if it is partially damaged.

■ The large block is made of SiC material, which has superior wear resistance and spalling resistance compared to conventional chamots and high alumina refractory bricks, so it is highly durable and has a long lifespan. By the way, regarding the wear resistance, the test results are as follows.
Approximately 10 times better than conventional chamots and high alumina materials (wear amount: 35.1 cm' for conventional products - 3.5 cm for 5iC materials), bending strength is approximately 2.3 times that of conventional products (bending strength of 1400°C) X After heating for 3 hours, 130 kg/cm −
= S i C quality 3.00 kg/cm'').

■ Since each large block is attached individually, even if one block is damaged or falls off, it can be partially repaired, minimizing repair costs.

■ Compared to conventional brick masonry construction, construction is easier and the construction period can be significantly shortened.

■ All dry types allow for significant energy savings and stable operation.

■ The center of the large block is hollow to reduce the cost.
It is also possible to press-fit an inexpensive monolithic refractory material into the SiC block.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view showing an example of the structure of a large block according to the present invention, Fig. 2 is a vertical cross-sectional view showing a part of the above large block attached to the upper part of the blast furnace shaft, and Fig. 3 is a large block similar to the above. FIG. 3 is a vertical cross-sectional view showing an enlarged block.

Claims (1)

[Claims] The front, back, left and right sides, and top and bottom surfaces are made of SiC material with excellent wear resistance and spalling resistance.
A large block of the required thickness is filled with refractory material inside and has an integral structure, and is installed along the inner surface of the steel shell through fireproof insulation material, and the joints between the blocks are filled with fireproof insulation material. A blast furnace shaft refractory structure characterized by comprising: