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Jiangsu Guohao Refractory Technology Co.,Ltd.
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| Application of refractories in various industries |
Publisher£ºadmin AddDate£º2018/10/9 Read£º2444times |
Looking from the development of refractory factories in China, although great progress has been made in recent years, the current situation of refractory industry is still not suitable for the development of various industries in the national economy, especially the high-temperature industry, and there is still a certain gap between the developed countries and the developed countries. Size application! However, its most common applications are in the following 5 areas. Let's talk about Xiaobian refractories in Henan.
(1) refractories for steelmaking systems
Refractories for steelmaking systems include converters, electric furnaces, refinery furnaces, ladles and tundish. In electric furnaces, dry vibrating materials, prefabricated or cast-in-situ furnace covers or furnace covers: triangles and other parts, have achieved better results; in converters and electric furnaces, the damage is usually repaired by refractory spraying paint, the methods include manual repair, wet, dry or flame spraying and slag splashing. In the converter, slag splashing technology is widely used to protect the furnace, the furnace life can reach more than 10,000 times; there are many kinds of refining furnace outside the furnace, RH and DH degassing device insertion tube lining, generally with high alumina refractory castable into a whole, service life of 20-80 times. Ladle and tundish are important accessory equipments of steelmaking furnace, and also the thermal equipments which consume most refractories. In the past, ladles were built with fired bricks such as clay refractory bricks, high alumina refractory bricks, semi-silica bricks and paraffin bricks. Their service life was 10-70 times. When ladle blowing or continuous ingot casting is used, the ladle life decreases sharply because of high exit temperature and long residence time. Therefore, many countries attach great importance to the development of lining materials, and have made significant progress. The converter in Anshan Iron and Steel Group Co. uses 200 t ladle with aluminium-magnesium castable and self-flowing material for lining, the ladle life is about 95 times and 80 times respectively; the converter in Baosteel uses 300 t ladle with high-purity aluminium-magnesium castable for lining, after repairing, the ladle life is generally about 260 times, and the refractory consumption is less than 1.78 kg per unit; many steel mills in the country are not more than 100 t ladle, using new technology. The age of the aluminum magnesia refractory castables is about 90 times, and the cost of pouring steel is 5.50~7.50 yuan per ton of steel. The tundish lining is made of insulating plate or magnesia coating, and the slag retaining weir is made of mullite, aluminum magnesia and magnesia refractory castables, which can meet the technical requirements of continuous casting steel. The overall spray gun for refining is used for ladle argon blowing or ladle powder injection. High alumina refractory castable is used above slag line, low cement corundum refractory castable is used from slag line to nozzle, and the whole wrapping lining is formed by vibration molding. Shanghai Baosteel uses this gun to blow argon for 3-5 minutes per furnace. The life of each lance is about 50 stoves, i.e. 150-250 minutes. Shougang uses this gun for powder injection and its life is 30-55 minutes.
(two) refractories for ironmaking systems
Refractories for ironmaking systems include sintering, coking and high aluminum and their subsidiary equipment. The service life of fireproof plastic and clay bonded refractory castables or phosphoric acid refractory castables prefabricated block hoisting for belt sintering machine ignition furnace is 3-6 years. When the wire ignition device is used, the top pressure of the furnace is much lower, the working conditions of the furnace are better, and the lining can be made of lightweight and high strength refractory castable or refractory fibers and their products, and the better effect can be obtained; the refractory castable is used to pour the heat insulation layer, the covering layer and the door of the coke oven top, and the head of the furnace is damaged, the coating is used to repair. In addition, CDQ equipment also uses heavy or light refractory castables; the blast furnace is a continuous production of iron-making equipment. Small blast furnaces were hoisted and masonry with aluminate cement and phosphoric acid high alumina refractory castables prefabricated blocks. Resin bonded alumina-carbon unburned bricks are now commonly used for masonry. Silicon carbide castables are used for water wall of large blast furnace, refractory castables and silicon nitride fillers are used for bottom cushion and surrounding brick seams, and refractory pressing materials and refractory spraying coatings are used for repairing lining damage in order to prolong the service life of the furnace to 10 years or even 15 years. The taphole of blast furnace is usually blocked by loose Al2O3-SiC-C mud, which can ensure stable tapping and normal operation. The blast furnace tapping hook is originally made of fire-resistant ramming material, and the consumption per ton of iron is about 1.1kg. Now poured with low porosity dense refractories, the amount of iron in one pass is about 100,000 tons, the cumulative amount of iron in the first generation ditch is about 900,000 tons, and the unit consumption of refractory iron per ton is less than 0.38 kg. At the same time, self-flowing refractory castables and non-baking refractory castables are also used in the tapping hook of blast furnace. Hot blast stove is the key accessory equipment of blast furnace. Lining of hot blast stove for medium and small blast furnaces is constructed with precast blocks of refractory castables. Hot blast stove burners can be built with refractory castable prefabricated blocks or irrigated in situ, and the ball top is irrigated with castable lining. The body of large-scale hot blast stove depends on the first layer of lightweight coating with a volume density of about 1.3g/cm3, and the ball top is sprayed with an acid-proof coating to form an integral lining. Corundum refractory castable and other materials are used for on-site pouring, and good results are obtained. Torpedo-type molten iron tanks and mixing furnaces generally use refractory pouring partly or completely. The injection material can also be repaired by fire-resistant spray coating, and the effect is good.
(three) refractories for building materials systems
Refractories for building materials systems include cement, glass and ceramics. High alumina phosphate or magnesia and magnesia chrome unburned bricks for cement kiln lining have a service life of 6-18 months, and amorphous refractories are also used locally. In the rotary kilns of large cement plants such as Jidong and Liuzhou, the usage of refractory castables is 19%-35%. The main types of refractory castables are low cement refractory castables, aluminate cement refractory castables, silica carbide refractory castables and insulating castables, etc. In the glass industry, tin troughs on float glass production lines are made of refractory castables. . In addition, when the glass tank is damaged, the silicon repair material is used for repair. Silicon insulating castables are usually used for the heat preservation of new kilns, and silicon carbide refractory castables and lightweight refractory castables are sometimes used for ceramic kilns.
(four) refractories for rolling system
There are many kinds and large quantities of refractory industrial furnaces for steel rolling system. The operating temperature is generally below 1400 C, all of which are flame furnaces. The refractory kiln can be lined with amorphous refractory, and good economic results are obtained. The steel rolling reheating furnace uses refractory plastic as its lining and has a long service life. For example, the large walking beam reheating furnace of WISCO has been used for more than 25 years and is still in use. Using clay and refractory castables to irrigate the lining as a whole, the service life is usually 4~10 years. For regenerative heating furnace, micro-expansion refractory castable should be used as lining. It has been used for more than two years and is intact. It is well known that the reheating furnace for forging steel can be used for more than 2 years by using brick lining and bonding refractory castables for 2 to 5 months. The service temperature of the reheating furnace for rolling steel is less than 1400 C and it is operated intermittently. The production practice at home and abroad has proved that the lining material should be Al2O3 < 65%, dried and dried. After 1400 20~25Mpa, the compressive strength is less than 60Mpa. Because the refractory castables with high aluminum content and high strength have poor thermal shock resistance and are easy to spall and crack when used, which affects their life.
(5) In the petrochemical industry, refractories used in other industrial systems are lightweight castables with a volume density of 0.5-1.0g/cm3 for tubular heating furnaces, which are constructed by hand smearing or spraying, and have a service life of about 5 years. The refractory material is used to spray lining, and good results are obtained. Amorphous platinum refractories are also widely used in platinum reforming units and ethylene plants. Especially, the wear-resistant refractory castable has been used in platinum reforming unit, which can cancel the refractory used in heat-resistant steel tortoise shell mesh system, and its life has also been improved. The lining of various converters, operating at temperatures of 600-1500 C, generally uses aluminate cement refractory castables, low cement refractory castables and corundum castables, etc., and has a service life of 3-6 years; in the nonferrous metallurgical industry, thermal equipment such as closed blast furnaces, flash furnaces, electrolytic tanks and rolling reheating furnaces are partially unshaped refractories. Lining. Recently, anti-penetration refractory castables have been widely used in aluminum reduction cells, and satisfactory results have been achieved. Amorphous refractories are the earliest and most common used on the lining of steam boilers. Generally, aluminate cement is used for heavy or light refractory castables. |
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