Analysis of the damage mechanism and preventive measures of magnesia carbon bricks in refined steel ladle

The damage mechanism of magnesia carbon bricks in refined steel ladle is complex, involving chemical reactions, physical erosion, and operating processes. The following is a detailed analysis of its damage mechanism:

Chemical reaction erosion oxidation and decarburization: The carbon in magnesia carbon bricks easily undergoes oxidation reactions with oxygen, water vapor, etc. in the air at high temperatures to form a decarburization layer. The formation of the decarburization layer exposes the magnesia matrix, which is then eroded by slag. In addition, MgO and C in magnesium carbon bricks will also undergo self-consumption reactions at high temperatures, resulting in a loose brick structure.

Slag erosion: The slag in the refined steel ladle has complex components, such as SiO₂, CaO, Al₂O₃, FeO, etc. At high temperatures, these components will react chemically with magnesium carbon bricks to form low-melting point compounds, resulting in damage to the brick structure. Especially in the slag line area, the damage rate is faster due to the more severe slag scouring and erosion.

Physical erosion and mechanical scouring: The stirring and argon blowing of molten steel during the refining process will produce strong mechanical scouring force, causing wear on the surface of magnesia carbon bricks. Especially in the slag line, the erosion is more serious due to the repeated scouring of molten steel and slag.

Thermal stress effect: The temperature in the refining ladle fluctuates greatly, and the magnesia carbon bricks will experience cyclic changes of thermal expansion and contraction during operation, generating thermal stress. When the thermal stress exceeds the bearing capacity of the brick body, it will cause the brick body to crack and peel off.

Operation process factors Refining process: Different refining processes have different degrees of damage to magnesia carbon bricks. For example, vacuum degassing, argon blowing and stirring processes will intensify the scouring and erosion of slag on magnesia carbon bricks.

Slag control: The chemical composition and physical properties of slag have an important influence on the erosion of magnesia carbon bricks. Changes in factors such as slag basicity, MgO content, and FeO content will affect the erosion rate.

Preventive measures

In view of the above damage mechanism, the following preventive measures can be taken to extend the service life of magnesia carbon bricks:

Optimize the refining process to reasonably control the temperature, time, stirring intensity and other parameters in the refining process to reduce the damage of mechanical scouring and thermal stress to magnesia carbon bricks.

Strengthen slag control and reduce its erosion on magnesia carbon bricks by adjusting the slag composition and physical properties. For example, increase the MgO content in the slag and reduce the FeO content.

Improve the quality of magnesia carbon bricks. Select high-purity magnesia sand raw materials and high-quality flake graphite as raw materials to ensure that the chemical composition of magnesia carbon bricks is stable and the impurity content is low.

Optimize the preparation process of magnesia carbon bricks to improve the density and strength of the products. For example, use advanced molding technology and sintering technology to reduce porosity and improve erosion resistance.

Improve the masonry process to optimize the structural design of the refractory lining and reduce the influence of stress concentration and mechanical scouring on magnesia carbon bricks. For example, use reasonable masonry methods and brick design to reduce the width of brick joints and improve overall stability.

Strengthen the quality control and acceptance work during the masonry process to ensure that the masonry quality of the refractory lining meets the standard requirements.

Strengthen maintenance and management Regularly inspect and maintain the refining ladle to promptly discover and deal with the damage of magnesia carbon bricks.

Strengthen the training and management of operators to improve their operating skills and sense of responsibility. For example, formulate reasonable operating procedures and emergency plans to deal with emergencies.

In summary, by optimizing the refining process, improving the quality of magnesia carbon bricks, improving the masonry process, and strengthening maintenance and management, the service life of magnesia carbon bricks in the refining ladle can be effectively extended and its damage rate can be reduced.