What is ladle castable?
Ladle castable is an amorphous refractory material used for ladle lining, mainly made of raw materials such as corundum, magnesia, spinel, etc. It has the characteristics of easy construction, good corrosion resistance, erosion resistance, and thermal shock resistance, and is widely used in the casting wall and permanent layer of large and medium-sized ladles. According to the latest industry standards released in July 2025, this type of material can be divided into three categories based on its usage location: highly wear-resistant, high-temperature resistant, and heat-insulating. It can effectively improve the service life of steel ladles and ensure stable quality of molten steel.
How to mix ingredients and formula
The core components of ladle castable determine its high temperature resistance and slag resistance, and the formula may be adjusted under different parts and working conditions.
Basic raw materials: Mainly using fused alumina, α - Al2O3 ultrafine powder, and CA-70 or 80 cement as binders, some high-purity products will add fused magnesia powder and aluminum rich spinel powder.
Additive optimization: In order to enhance slag resistance and toughness, a small amount of Cr2O3 (chromium oxide) or steel fibers are often added. For example, overseas research has shown that adding Cr2O3 to aluminum magnesium castables can significantly improve corrosion resistance; The amount of steel fiber added is usually 2% to 6% of the weight of the casting material, which can improve crack resistance and impact resistance.
Reference ratio: The specific formula varies depending on the patent and manufacturer. For example, a high-performance formula contains 50-75% high alumina aggregate, 1-10% magnesia alumina spinel powder, and 1-7% microsilica powder; Another patent shows that the proportion of plate-like corundum particles (3-6mm) is about 30%, and the binder containing MgO 6.5% to 7.5% can improve density and strength.
How to choose between classification and performance
When selecting ladle castables, performance indicators should be matched based on the specific parts of the ladle (such as the ladle wall, bottom, and edge) and smelting conditions (such as refining furnaces and converters).
Material classification:
Aluminum magnesium material: mainly used for wall cladding, with strong resistance to alkaline slag. In situ generation of magnesium aluminum spinel can improve thermal shock resistance.
Corundum spinel: With high volume stability, it is commonly used for bottom wrapping to prevent arching and slag infiltration.
Self flowing castable: It can flow without vibration and is suitable for areas with dense or narrow anchoring components, such as around the base brick.
Performance indicators: High quality ladle castables need to have high room temperature strength, low porosity, and high flexural strength. For example, after optimization by a steel plant, the flexural strength of the ladle edge castables increased by about 9.6MPa, while the apparent porosity decreased.
Application scenarios:
Iron ladle: It needs to withstand the erosion of molten iron at 1300-1500 ℃, and the Al ₂ O Ⅲ content is usually ≥ 85%.
Refining ladle: The slag line has harsh conditions and is often used in conjunction with magnesia carbon bricks. The castable needs to strengthen the matrix to reduce slag infiltration.
How to do construction and application
The construction process directly affects the service life of the casting material, and it is necessary to strictly control the mixing, pouring, and curing processes.
Mixing requirements: Use a forced mixer, dry mix for 2 minutes, then wet mix with water for 4 minutes, with a total time of not less than 6 minutes. The reference water addition rate is 5.2~5.5%, and temporary water addition is strictly prohibited.
Pouring and curing: After pouring, it needs to be compacted by vibration and hardened for 24 hours before demolding. The normal curing time should be greater than 3 days, and baking should be carried out according to the system to prevent cracking.
Attention: Construction materials must not be damp, and mixing water must be cleaned; It is recommended to use optimized high alumina castables for key areas such as the edge of the package to reduce the risk of slag sticking and leakage.
