Metal Zone Bricks For Ladle

The following factors are considered to be most influencing ones for the lining life of steel ladles:

Slag basicity and fluidity of molten steel
Long holding time of high temp. molten steel
Stirring action of molten steel
Thermal spalling from tem.
Fluctuation
Ladle handling method
Ladle structural deign
Process constraints
Tap conditions
Lining/repairing method, etc.

Lining of steel teeming ladle is divided into several zones including slag zone metal zone and bottom zone. The required characteristics of Refractories for each zone are as under

0 - Most important
$ - Important
X - Moderate

For metal zone, high alumina bricks were widely used. However, it has many problems such as structural spalling by slag penetration, damage to joints by slag & metal and shrinking after 25-30 campaigns.

Alumina-magnesia spinal bricks show batter performance than high alumina brick in this area due to high corrosion resistance, slag resistance and tight brick joints.

Recently, Alumina-magnesia graphite (AMG) bricks are used successfully. The opening at the brick joints is overcome by combining MgO in Al2O3-C bricks to provide a controlled/gradual continuous expansion of brick by spinal formation. With this combination, the joints will bot open during thermal cycling of the ladle, thus reducing pre-mature wear at the joints and avoiding steel & slag penetration to the cold end and consequently unexpected ladle break through MgO addition also improves corrosion resistance. However, excessive addition of MgO causes excessive expansion of the bricks, which may cause peeling.