JPH0522673B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an expansion absorbing joint material between blocks in the construction of carbon bricks used for lining molten metal melting furnaces such as blast furnaces. (Prior Art) Large-sized carbonaceous blocks are used as refractories for lining blast furnaces in order to reduce the number of joints that are unavoidable in the construction of refractories. In the furnace, carbonaceous blocks suffer from abrasion due to contact with charged raw materials, physical and chemical attack by hot metal, slag, etc., as well as disintegration due to the intrusion reaction of low-boiling metal vapors, especially alkali metals, generated from the raw materials, and Damage occurs due to oxidation caused by locally present oxygen, cracking caused by thermal shock, etc. If the joints are weak, damage to the carbon blocks will be further accelerated. The dimensional accuracy of the carbon blocks is usually ±0.5 mm in order to adjust the alignment level during construction and keep the gaps between joints small. When blocks are actually constructed three-dimensionally, the joint gaps between all blocks need to be as small as possible, 0.3 to 0.7 mm. This is because hot metal enters and the life of the refractory layer is shortened. As a method of eliminating the gaps caused by the above-mentioned open joints, for example, as shown in Japanese Patent Publication No. 57-48507, construction is carried out using mortar joint material, but due to the viscosity of the mortar joint material and the skill of the constructor, There are differences in construction content depending on the degree. That is, it is difficult to apply the mortar to the horizontal and vertical surfaces of the block under the same conditions, and in particular, it is difficult to reduce the thickness of the mortar layer, making it difficult to obtain the desired dimensional accuracy. Furthermore, when the carbon blocks expand due to heat, the blocks come into contact with each other.
Although a part of the expansion is absorbed by the annular stamp layer provided on the outer periphery of the building layer of the blocks, problems may arise in the circumferential direction where the blocks may break due to contact with each other. In order to solve this problem, we tried to reduce the shape of the large block and increase the number of joints to absorb expansion, and to sandwich mortar or cardboard into all or some of the joints, and by increasing the temperature, the cardboard There is a method of absorbing the expansion by burning and dissipating the gas. However, increasing the number of joints
This problem arose before the blocks became larger in that corrosion resistance deteriorated due to deterioration of joint corrosion resistance and thermal conductivity, and this problem was brought about by technological trends. In addition, in the method of sandwiching cardboard,
When a part of the cardboard disappears, the stress of the collision is not applied evenly to the block surface, causing the block to break.Also, organic materials such as cardboard have poor corrosion resistance, and the burned-out joint gaps A problem arises in that hot metal enters into the block, accelerating wear and tear on the block. (Object of the Invention) The present invention has been made to solve the above-mentioned problems with joint materials. (Structure of the Invention) The details of this invention will be explained below. The gist of this invention resides in an expanded graphite sheet-like brick expansion-absorbing joint material, which is characterized by compression-molding expanded graphite together with carbon or resin fiber mesh to form a compressible sheet. Expanded graphite is Flake graphite,
Natural graphite, such as Vein graphite, is treated with a strongly oxidizing solution such as concentrated sulfuric acid, e.g.
The volume has been significantly expanded by 80 times. If this expanded graphite is compressed as it is, a sheet-like molded body can be obtained. In forming the sheet, expanded graphite is formed into a sheet with a thickness of, for example, about 2 mm using a press together with carbon or resin fiber mesh at a molding pressure of, for example, about 10 kg/cm ² . The sheet formed in this manner easily shrinks in volume as pressure increases, and has a large shrinkage ratio as shown in Table 1.

[Table] Molded sheet - Thickening pressure
Sheet thickness *Shrinkage rate=

Claims (1)

[Claims] 1. An expanded graphite sheet-like brick expansion-absorbing joint material characterized by compression-molding expanded graphite together with carbon or resin fiber mesh into a compressible sheet.