Slag Resistance of Zirconia Refractory Materials

The slag resistance of zirconia refractory materials refers to their ability to resist slag erosion at high temperatures, which is one of the key indicators for evaluating the performance of refractory materials. Below is a detailed analysis of the slag resistance of zirconia refractory materials:

1. Overview of Slag Resistance

The slag resistance is mainly affected by the chemical composition, mineral structure, texture of the refractory material, and the properties and interaction conditions (such as temperature, time, and slag flow rate) of the slag. The mechanism of slag erosion is complex and includes physical and chemical actions such as infiltration, dissolution, and molten material scouring.

2. Characteristics of Zirconia Refractory Materials

• Chemical Stability: Zirconia (ZrO₂) has excellent chemical stability and can maintain its structural integrity at high temperatures, making it less prone to chemical reactions with slag.
• High Melting Point: The high melting point of ZrO₂ enables it to retain good physical properties in high-temperature environments.
• Resistance to Metal Erosion: Zirconia refractory materials demonstrate good resistance to metal erosion, which provides them with broad application prospects in specific high-temperature metallurgical environments.

3. Slag Resistance Performance of Zirconia Refractory Materials

• Experimental Verification: Research has shown that under high temperatures (1500-1600°C) and in the presence of high-alkaline slag formers, the cubic zirconia phase in ZrO₂-MgO refractory materials, made from zircon concentrate, does not decompose. This indicates that the material can resist slag erosion at high temperatures with different slag compositions, demonstrating excellent slag resistance.
• Application Example: Due to their slag resistance, zirconia refractory materials are widely used in casting nozzles and slide gate plates for continuous casting machines, which are used to manufacture special grades of steel. In these applications, the refractory material must withstand prolonged contact with slag at high temperatures without significant erosion.

4. Factors Affecting Slag Resistance

• Chemical Composition: When the chemical composition of the refractory material is similar to that of the slag, high-temperature melting interactions are more likely to occur, accelerating chemical reactions and the erosion process. Therefore, selecting appropriate refractory materials that match the specific slag composition is key to improving slag resistance.
• Mineral Composition and Structure: Refractory materials with a high proportion of high-melting-point crystalline minerals and a uniformly distributed high-viscosity liquid phase tend to have better slag resistance. Additionally, reducing impurities in the matrix and increasing the rate of direct bonding can enhance slag resistance.
• Temperature: High temperatures increase the liquid phase in both the refractory material and the slag while reducing the viscosity of the liquid phase, which accelerates the chemical erosion process. Therefore, refractory materials used in high-temperature environments must have higher slag resistance.

5. Conclusion

Zirconia refractory materials, with their excellent chemical stability, high melting point, and resistance to metal erosion, have broad application prospects in the high-temperature metallurgical field. Their slag resistance has been experimentally validated and proven reliable in practical applications. However, in actual use, it is essential to select suitable refractory materials based on the specific slag composition and working conditions to improve their slag resistance and extend their service life.