Torpedo ladle is a type of equipment commonly used in the steelmaking process for transporting and temporarily storing high-temperature molten iron. Because the molten iron is hot (typically between 1300-1500°C) and contains highly corrosive components, the lining of a torpedo ladle requires high-performance refractory materials. The following are commonly used refractory types and their characteristics:
1. High-Alumina Bricks
▸Features: Contains a high proportion of alumina (Al₂O₃), resulting in high refractoriness and excellent resistance to molten iron corrosion.
▸Applicable Locations: Areas of the ladle lining where temperatures are high and corrosion is relatively low, such as the upper and middle areas.
▸Advantages: Offers high refractoriness and mechanical strength, strong thermal shock resistance, and resistance to corrosion by oxides in the molten iron.
2. Magnesia-Carbon Bricks
▸Features: Made of magnesium oxide (MgO) and carbon (C), it offers excellent resistance to alkaline slag and thermal shock.
▸Applicable Locations: Thermal shock zones and areas of severe corrosion in torpedo linings, often used at the slag line of torpedo-type hot metal ladle.
▸Advantages: Excellent high-temperature performance, capable of withstanding high-temperature corrosion from molten iron; excellent thermal shock resistance, and strong resistance to slag corrosion.
3. Silicon Carbide Bricks (SiC Bricks)
▸Features: Contains silicon carbide (SiC), offering high thermal conductivity and corrosion resistance.
▸Applicable Locations: The furnace floor and impact zone of the hot metal ladle, often used in the receiving and tapping areas of torpedo-type hot metal ladle.
▸Advantages: High hardness, wear resistance, and corrosion resistance, capable of withstanding erosion by molten iron and slag, maintaining good stability in high-temperature oxidizing atmospheres.
4. Alumina-Magnesia-Carbon Bricks
▸Features: Combining the advantages of alumina, magnesia, and carbon, it combines high strength and corrosion resistance.
▸Applicable Locations: Areas requiring high strength and corrosion resistance.
▸Advantages: Excellent thermal shock resistance, suitable for high-temperature impact of molten iron.
5. Corundum Bricks
▸Features: Made of corundum (with an Al₂O₃ content of over 90%), it offers high refractoriness and excellent corrosion resistance.
▸Applicable Locations: Areas subject to severe high-temperature impact.
▸Advantages: Strong high-temperature tolerance and chemical stability.
6. Spray-coated Refractory Materials
▸Features: A refractory coating, typically containing high aluminum or magnesium content, is sprayed onto the surface of the ladle lining. This allows for timely repair of damaged areas without removing the existing lining.
▸Applicable Locations: Repairing ladle linings and extending service life.
▸Advantages: Easy application and excellent repair results. Excellent adhesion to the existing lining material, forming a strong repair layer.
7. Castables
▸Features: Composed of refractory aggregate and binder, it is poured on-site to form an integrated lining.
▸Applicable Locations: Complete lining construction or localized repairs.
▸Advantages: Good integrity and suitable for complex shapes. The formula can be adjusted to meet different refractory requirements based on specific application requirements.
Refractory Selection Criteria
▸Molten Iron Temperature: The refractory material must be able to withstand high temperatures (≥1500°C).
▸Corrosiveness: The refractory material must be resistant to chemical attack from the molten iron and slag.
▸Mechanical Shock Resistance: The refractory material must be able to withstand the mechanical impact of molten iron entering the tank.
▸Thermal Shock Resistance: The refractory material must have high thermal shock resistance to withstand rapid temperature fluctuations.
In summary, torpedo-type ladle linings typically utilize a composite lining structure, with a well-balanced combination of refractory materials to ensure the longevity of the lining and the stability of molten iron transportation.