In high-temperature industries such as glass manufacturing, metallurgy, and chemical processing, the selection of kiln lining materials directly dictates equipment lifespan, product quality, and production costs. Fused Cast AZS Blocks have become an irreplaceable refractory material for critical areas of high-end glass tank furnaces, thanks to their extremely high refractoriness, superior resistance to glass liquid corrosion, and dense microstructure.

What is Fused Cast AZS Block?

Fused Cast AZS block, fully named Fused Cast Zirconia Corundum Brick, derives its name from the abbreviations of its three main chemical components: Alumina (Al₂O₃), Zirconia (ZrO₂), and Silica (SiO₂).

This material is manufactured by melting selected zircon sand and industrial alumina powder in an electric arc furnace at temperatures exceeding 2000°C, followed by casting. Its microstructure consists of a eutectoid of corundum and baddeleyite phases filled with a glassy phase. This unique structure endows it with exceptional resistance to the erosion and mechanical scouring of molten glass.

Classification by ZrO₂ Content

Fused Cast AZS blocks are globally categorized into three grades based on ZrO₂ content—33#, 36#, and 41#. Corrosion resistance improves progressively with higher Zirconia content.

• AZS-33# (ZrO₂ Content 32-36%)
  Features a dense microstructure that offers excellent resistance to glass melt corrosion, minimizing the risk of stones, defects, or blisters. It is the most widely used grade, suitable for the superstructure of the melter, sidewalls of the refiner, tank bottom paving, and channels.
• AZS-36# (ZrO₂ Content 35-40%)
  In addition to the eutectic structure found in 33#, AZS-36# contains a higher proportion of interlocked zirconia crystals and reduced glassy phase content. This significantly enhances corrosion resistance and reduces contamination of the glass melt. It is ideal for areas with faster flow rates and higher temperatures, such as sidewall blocks, paving blocks, and doghouse blocks.
• AZS-41# (ZrO₂ Content 40-44%)
  Contains a higher volume of uniformly distributed zirconia crystals, offering the best corrosion resistance in the AZS series. With low glassy phase content, it exhibits exceptional resistance to pollution from molten glass. It is designed for the most severely eroded critical areas, such as the throat and dam blocks.

Core Performance Advantages

• Superior Corrosion Resistance: Corrosion rate against soda-lime glass is ≤1.5mm/24h (at 1500°C), significantly outperforming standard refractory bricks.
• High-Temperature Stability: Load softening temperature ≥1700°C, ensuring no shrinkage or deformation in glass furnaces operating above 1600°C.
• Low Contamination: Produced via the oxidized method, the blister exudation rate is ≤2% (at 1300°C), ensuring the glass melt remains uncontaminated.
• Dense Structure: Apparent porosity ≤2% and bulk density of 3.7-3.9g/cm³, effectively resisting glass penetration.
• Long Service Life: Typically achieves a lifespan of 5-8 years in standard glass kilns.

Primary Application Areas

• Glass Industry: Covers approximately 90% of application scenarios. Used in tank walls (36#), doghouses (41#), throats (WS type), regenerators, melter bottom paving, and working channels.
• Steel Metallurgy: Used in ladle slide gates and RH degasser snorkels for resistance against molten steel erosion.
• Chemical Sector: Used as lining for coal gasification furnaces due to resistance against acidic media.
• Electronic Glass: Critical components for LCD and photovoltaic glass furnaces, ensuring high-purity production requirements.

Fused Cast AZS blocks occupy an irreplaceable position in global glass tank furnaces due to their卓越 corrosion resistance, thermal stability, and dense microstructure. Selecting high-quality oxidized-method AZS blocks and choosing the appropriate ZrO₂ grade and casting method for specific kiln zones are key to ensuring long-term, stable kiln operation.