(1) Steelmaking system

The steelmaking system includes converters, electric furnaces, out-of-furnace refining furnaces, ladle and tundish equipment. In electric furnaces, dry vibrating materials, prefabricated or cast-in-place furnace covers or furnace covers: triangle areas, etc., have good results; in converters and electric furnaces, fire-resistant spray coatings are generally used to repair the damage. The methods are as follows: Manual filling, wet, dry or flame spraying and slag splashing to protect the furnace. In Liaoning magnesia-chrome bricks, slag splashing protection technology is commonly used in converters, and the furnace age can reach more than 10,000 times; there are many types of refining furnaces outside the furnace, and the tube linings of RH and DH degassing devices generally use high aluminum High-quality refractory castable is poured into a whole, and the service life is 20 to 80 times. Ladle and tundish are important ancillary equipment for steelmaking furnaces, as well as thermal equipment that consumes a lot of refractory materials. In the past, ladle was generally built with fired bricks such as clay refractory bricks, high alumina refractory bricks, semi-silica bricks and wax stone bricks, with a service life of 10 to 70 times. When ladle blowing or continuous ingot casting is used, the age of the ladle drops sharply due to high steel temperature and long residence time. Therefore, various countries attach great importance to the development of lining materials, and significant progress has been made. Anshan Iron and Steel converter uses a 200t ladle, which is lined with aluminum-magnesium castables and self-flowing materials, and the ladle age is about 95 and 80 times respectively; Baosteel uses a 300t ladle for converters, which is lined with high-purity aluminum-magnesium castables, and the ladle age is average after repair At about 260 times, the unit consumption of refractories is below 1.78kg; many steel plants use new technology aluminum-magnesium refractory castables for ladle not larger than 100t, and the ladle age is about 90 times, and the cost of casting steel is 5.50~7.50 per ton of steel. yuan. The tundish bag lining is made of hot plate or magnesia paint, and the slag barrier is made of mullite, aluminum-magnesium and magnesia refractory castables, which can meet the technical requirements of continuous steel casting. The integral spray gun for refining outside the furnace is used for ladle argon blowing or ladle powder spraying. The part above the slag line is made of high-aluminum refractory castable, and the part from the slag line to the nozzle is made of low-cement corundum refractory castable, which is vibrated to form an integral wrapping lining. Shanghai Baosteel uses this gun to blow argon. The argon blowing time for each furnace is 3 to 5 minutes, and the life of each spray gun is about 50 furnaces, which is 150 to 250 minutes; steel is used for powder spraying, and its life is 30 to 55 minutes.

(2) Ironmaking system

The iron system includes sintering, coking, blast furnace and its auxiliary equipment. The ignition furnace of the belt sintering machine is made on site with refractory plastic and clay combined with refractory castable, or prefabricated with phosphoric acid refractory castable, and its service life is 3 to 6 years. When the linear ignition device is used, the furnace top pressure is more reduced and the furnace working conditions become better. Lightweight refractory castables or refractory fibers and their products can be used as linings to obtain better results; the coke oven roof insulation layer, The cladding layer and the furnace door are poured with refractory castables. When the furnace head is damaged, spray paint is used to repair. In addition, CDQ equipment also uses heavy or light refractory castables; blast furnaces are ironmaking equipment for continuous production. Small blast furnaces were once built with aluminate cement and phosphate high-alumina refractory castable prefabricated blocks, and now they are generally built with resin-bonded aluminum-carbon non-burned bricks. Large-scale blast furnace water walls use silicon carbide castables, furnace bottom cushions and surrounding brick joints use refractory castables and silicon nitride fillers. When the furnace lining is damaged, use refractory injection materials and refractory spray coatings to repair, in order to extend the service life. The furnace age reaches 10 or even 15 years. The tap hole of the blast furnace is generally blocked with loose Al2O3-SiC-C gun mud, but the tap hole is stable and the operation is normal. The blast furnace tapping hook was originally rammed with refractory ramming material, and the unit consumption per ton of ditch material is about 1.1kg. At present, low-porosity compact refractories are used for casting, and the amount of iron passing through once reaches about 100,000 tons. The cumulative iron passing volume of one generation of ditch age is about 900,000 tons, and the unit consumption of refractory iron per ton is less than 0.38kg. At the same time, artesian refractory castables and non-baking refractory castables have also been used on the tap hooks of blast furnaces. Hot blast furnaces are key auxiliary equipment for ironmaking blast furnaces. The lining of medium and small blast furnace hot blast furnaces is built with refractory castable prefabricated blocks. The burner of the hot blast stove can be built with refractory castable prefabricated blocks or cast on site, and the spherical top is casted with castable for working lining. The large-scale hot blast stove body relies on the first layer of light spray paint with a volume density of about 1.3g/cm3 on the furnace shell, and the dome is sprayed with a layer of acid-resistant spray paint to form an overall inner lining, using corundum refractory castables and other materials. Pouring has a good effect; the hot metal ladle and mixing furnace generally use refractory castables locally, and can also be repaired with refractory spray paint, which has a better effect.