The new breakthrough of the whole casting technology of the furnace cylinder, innovation and expansion, leading the new development of the industry

Release time:

2023-12-21

The use of the fourth generation of sialon carbon-nitrogen high-strength composite materials for the overall pouring of the blast furnace cylinder, the fundamental solution to the traditional masonry brick lining complex construction, gas and other problems, widely used in blast furnace cylinder maintenance, new blast furnace cylinder design, greatly improve the construction efficiency at the same time, reduce the cost of repair. At present, some of the domestic blast furnace maintenance, furnace cylinder pouring has been extended to the furnace belly, furnace waist and other parts.

01 Advantages of the overall casting technology for the furnace cylinder

According to the different working conditions of each part of the blast furnace, the different reasons for the erosion of each part, the blast furnace lining material will have different degrees of corrosion, the general use of thermal repair method to quickly repair the blast furnace lining. The overall casting of the furnace cylinder is a typical application of amorphous castables, and its application environment is even more complicated than that of the blast furnace body. Therefore, for materials and processes, factors such as operating environment temperature, mechanical erosion, and chemical erosion should be considered. On the one hand, the working lining is protected by hanging slag, and on the other hand, the material needs to have the best performance.

There are usually two schemes for furnace cylinder maintenance: combined brick building and furnace cylinder integral pouring. The former is usually used for the design of new blast furnace hearth, while the latter is often used for medium repair process hearth repair. In recent years, the new blast furnace also generally adopts the overall pouring method to design the hearth lining, from the following aspects:

(1) the combination of brick masonry, prefabrication cycle is long, and need to be pre-built, processing is difficult;

(2) Tuyere combination brick, brick type design is relatively complex, masonry is difficult, prone to masonry deviation, resulting in late start-up gas;

(3) the combination of brick materials, and can not form an effective slag iron viscous layer, along the brick lining service life is low.

West China furnace cylinder overall casting (patent number: ZL 201610353176.4), the use of West China fourth generation Sialon carbon and nitrogen high-strength composite materials, through the mold casting method to repair the furnace cylinder lining, the overall construction period of 7 days, its advantages are:

(1) eliminate the ceramic cup two big gap (ceramic brick between the gap, ceramic cup and carbon brick between the gap), to prevent water vapor, alkali metal and other harmful elements erosion carbon brick, effective protection of carbon brick;

(2) The high temperature sharp temperature drop zone can be left in the castable, the temperature inside the carbon brick is reduced to below 800 ℃, the thermal stress in the carbon brick is reduced, the appearance of the carbon brick ring crack and the brittle layer is reduced, and the thermal conductivity of the carbon brick is maintained. In the application of blast furnace longevity, as long as the thermal conductivity of blast furnace carbon bricks persists, without losing thermal conductivity due to ring cracking and embrittlement, the longevity of blast furnace is guaranteed;

(3) The castable for the furnace cylinder has good slag hanging property, and can form a stagnant layer on the hot surface, which can further protect the carbon bricks for the furnace cylinder. The semi-thermally conductive castable for furnace cylinder pouring is closely bonded with the carbon bricks. Heat can be transferred to the cooling wall through the carbon bricks with high thermal conductivity, and the temperature of the casting layer can be reduced to below 1150 ℃, thus forming an iron-carbon solidified layer to protect the castable, and then the castable protects the composite slag skin mechanism of the carbon brick.

02 the fourth generation of Sialon carbon nitrogen high strength composite castable

(1) The use of metal (Si/Al) ductility to achieve plastic forming, the use of nitriding and reducing atmosphere in the blast furnace to achieve the use of in situ synthesis of high-temperature enhanced phase (Si3N4/SiAlON), and non-oxide substrate to form a perfect mosaic structure, while achieving:

◆ Excellent resistance to chemical erosion

The use of the process with self-repair function

◆Good thermal shock resistance

(2) With the metal-non-oxide composite material system as the substrate, through non-oxide surface modification, the use of sol-gel molding process to achieve:

◆Good liquidity

◆Fast drying performance

◆ Overall stability after drying

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The new breakthrough of the whole casting technology of the furnace cylinder, innovation and expansion, leading the new development of the industry