Unshaped refractory materials are widely used in various industries. They have no fixed shape and are loose, slurry or mud paste. They can also be made into prefabricated blocks or form seamless integral structures. The following are the applications of unshaped refractory materials in several major industries:
I. Iron and steel industry
1. Ironmaking system
Belt sintering machine ignition furnace: Made on-site using refractory plastic and clay combined with refractory castables, or hoisted with prefabricated blocks of phosphoric acid refractory castables, with a service life of 3 to 6 years.
Coke oven: The top insulation layer, covering layer and furnace door are poured with refractory castables, and the furnace head is repaired with spray coating when it is damaged. Dry quenching coke equipment also uses heavy or light refractory castables.
Blast furnace: It is a continuous production ironmaking equipment. Small blast furnaces were once hoisted and built with prefabricated blocks of aluminate cement and high-alumina phosphate refractory castables. Now, resin-bonded aluminum-carbon unburned bricks are commonly used for masonry. Silicon carbide castables are used to pound the water-cooled walls of large blast furnaces. Refractory castables and silicon nitride fillers are used for the furnace bottom cushion and surrounding brick joints. When the furnace lining is damaged, it is repaired with refractory pressing materials and refractory spray coatings to extend the service life and make the furnace life reach 10 or even 15 years. The blast furnace taphole is generally blocked with loose Al₂O₃-SiC-C taphole mud, and the taphole is mainly cast with Al₂O₃-SiC-C refractory castables. At the same time, self-fluidizing castables are also used in the taphole.
Hot blast furnace: It is a key auxiliary equipment of the iron-making blast furnace. The lining of a small hot blast furnace is casted with refractory castables. The burner can be built with castable prefabricated parts or poured on site, and the dome is cast with refractory castables for the working lining. The furnace body of a large hot blast furnace is sprayed with a layer of light spray paint on the furnace shell, and the dome is sprayed with acid-resistant spray paint to form an integral lining to resist the corrosion of the furnace shell by sulfur-containing flue gas. The hot blast surrounding pipe, branch pipe, air supply pipe and hot blast valve are cast on site with corundum castables.
2. Steelmaking system
Electric furnace and converter: The damaged lining is generally repaired with spray paint, and the slag splashing furnace protection technology is generally used.
Out-of-furnace refining: There are many types. The insert pipe lining of the RH method and DH method degassing device is generally cast as a whole with high-aluminum castables.
Ladle and tundish: The aluminum-magnesium spinel castable for the ladle has achieved good application results. The tundish lining is made of insulation board or magnesium coating, and the slag weir is made of mullite, aluminum-magnesium and magnesium refractory castables, which can meet the technical requirements of continuous steel casting.
2. Building materials industry
The building materials system includes industrial sectors such as cement, glass and ceramics. Cement kiln linings use refractory bricks such as high-alumina phosphate or magnesium or magnesium-chromium, and unshaped refractory materials are also used in some areas.
3. Petrochemical industry
In the petrochemical industry, tubular heating furnaces use lightweight refractory castables with a volume density of 0.5~1.0g/cm³, which are constructed by manual application or spraying. Platinum heavy equipment and ethylene equipment also use a large number of unshaped refractory materials. In particular, wear-resistant refractory castables are used in platinum heavy equipment, and the heat-resistant steel tortoise shell mesh system can be eliminated. The linings of various converters are generally made of aluminate cement castables, low cement castables, corundum castables, etc.
4. Other industries
1. Aluminum electrolytic cells: Use anti-penetration refractory castables and non-stick aluminum castables to achieve satisfactory results.
2. Steam boilers: The lining uses unshaped refractory materials most commonly, and generally uses aluminate cement combined with refractory castables.
3. Fluidized bed boiler: using high-aluminum, corundum castables and plastics, which have high strength and good wear resistance, meeting the design and use requirements.
Unshaped refractory materials play an important role in industrial production due to their excellent performance and wide application fields. With the continuous advancement of technology and the deepening of application, the application prospects of unshaped refractory materials will be broader.
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