AZS stands for alumina (Al₂O₃)-zirconia (ZrO₂)-silica (SiO₂) in English. It is a high-grade refractory brick manufactured through an electric melting process. AZS bricks have become an irreplaceable key material for glass furnaces primarily due to their exceptional resistance to glass melt erosion and corrosion. Their unique eutectic structure—where zirconia crystals are embedded within a corundum and glass phase matrix—enables exceptionally long service life even in the most demanding furnace locations (such as tank walls, upper structures, and flow channels). This effectively minimizes glass defects, ensuring the purity and quality of glass products.

The numerical value in the model indicates the approximate percentage of zirconia (ZrO₂) in the brick. Different contents yield varying performance characteristics and application scenarios.

AZS 33 (approx. 33% ZrO₂): The most versatile and economical option, offering excellent erosion resistance. Widely used in areas exposed to molten glass, such as tank walls and bottoms.

AZS 36 (approx. 36% ZrO₂): Offers superior erosion resistance and lower glass phase exudation compared to AZS 33. Suitable for more demanding locations like flow holes, tank wall corners, and feed inlet corners, making it the preferred choice for critical areas in most furnaces.

AZS 41 (approx. 41% ZrO₂): The top-tier grade, offering the highest erosion resistance and glass phase exudation resistance with exceptional thermal stability. Specifically engineered for the most extreme furnace environments, primarily used in upper structures (large arches), breast walls, working sections, and furnaces producing high-quality glass like electronic glass and pharmaceutical glass.

Selection Criteria: Decisions should be based on the specific kiln location, type of molten glass (e.g., soda-lime glass, borosilicate glass), operating temperature, and target kiln life.

AZS bricks are primarily used in glass furnaces within areas directly exposed to high-temperature molten glass or subjected to the most severe erosion and corrosion from glass volatiles. These areas mainly include:

* Melting Section Pool Walls and Floor: Directly contact molten glass, enduring intense chemical erosion and mechanical abrasion.

Flow channels: Characterized by high glass flow velocity and temperature, these represent one of the most severely eroded zones in the furnace, necessitating high-performance AZS bricks (e.g., AZS 36/41).

Feed inlet corners: Subject to dual erosion from batch materials and molten glass, coupled with temperature fluctuations.

Upper structures (e.g., lintels, breastwalls): Though not in direct contact with molten glass, these components endure chemical erosion from alkaline vapors and flying particles. AZS 41 bricks with high zirconia content effectively resist this erosion, preventing defects like “mouse holes.”

Working section and feed channels: These ensure stable glass quality prior to forming.

When using AZS bricks, special attention must be paid to the following points:

Glass Phase Leaching: At high temperatures, a small amount of glass phase may leach from AZS bricks, potentially causing erosion of nearby refractories or defects such as slag inclusions and streaks when contacting molten glass. Therefore, during masonry work, AZS bricks in contact with sensitive areas should undergo surface polishing to minimize initial leaching.

Risk of Cracking: AZS bricks exhibit a relatively high thermal expansion coefficient and good thermal conductivity. During the kiln firing stage, the heating curve must be strictly adhered to, avoiding rapid temperature increases that could cause thermal stress concentration and cracking.

Oriented crystallization: Certain high-performance AZS bricks (e.g., inclined-cast bricks) feature an oriented crystalline structure, imparting directional resistance to glass melt erosion. During installation, bricks must be laid strictly according to their marked orientation (typically with the cast surface facing the hot zone or glass melt). Failure to do so will significantly reduce their service life.

To evaluate the quality of AZS bricks, the following key performance indicators must be considered:

Chemical Composition: Particularly zirconia (ZrO₂) content, which directly determines erosion resistance.

Bulk Density: Higher density typically indicates a denser structure, resulting in stronger resistance to permeation and erosion.

Porosity: Lower apparent porosity is preferable. Reduced porosity effectively prevents glass melt and atmosphere from infiltrating the brick interior, thereby delaying erosion.

Glass Phase Exudation Rate: Measured under specific temperature and time conditions. A lower exudation rate minimizes contamination of the glass melt and enhances the brick's high-temperature volume stability.

Resistance to Molten Glass Erosion: Tested via static or dynamic crucible methods, this is the most critical indicator for assessing service life.

Appearance and Dimensional Tolerance: High-quality AZS bricks feature smooth surfaces free of cracks, chipped corners, or other defects. Precise dimensions ensure fine, uniform masonry joints, extending the overall refractory lining's lifespan.

“Glass phase seepage” is a normal characteristic of AZS bricks during high-temperature use and typically requires no excessive concern. Due to the presence of a small amount of glass phase (amorphous phase) within the brick body, these glass phases slowly migrate to the brick surface under prolonged high-temperature conditions, forming a glaze-like protective layer. This protective layer actually helps to:

Slow further erosion: It seals pores on the brick surface, preventing molten glass from penetrating deeper into the brick.

Protect the brick structure: It forms a dynamic protective barrier.
This phenomenon is beneficial as long as high-quality AZS bricks are used and proper kiln-firing procedures are followed. The AZS bricks we supply undergo strict control over glass phase content and exudation to ensure optimal performance.

To ensure optimal performance and furnace longevity, observe the following points:

Proper Selection: Choose the appropriate AZS grade based on the furnace location (e.g., high-zirconia AZS-36 for pool walls in high-erosion zones) and the type of molten glass.

Precision Processing and Masonry: AZS bricks possess extreme hardness, requiring specialized diamond tools for cutting. Use compatible AZS-grade refractory mortar during installation, minimize joint widths (typically under 1mm), and strictly adhere to design drawings.

Strict Kiln Drying Curve Control: Newly constructed or repaired kilns must undergo slow, uniform heating following the manufacturer's provided drying curve. This is critical for releasing internal brick stresses and preventing cracking.

Professional Consultation: We recommend consulting our technical team before selection and installation. We will provide the most professional solutions tailored to your specific operating conditions.

The core advantage of AZS bricks lies in their exceptionally high resistance to chemical erosion, particularly their ability to withstand molten glass and acid/alkali corrosion far surpassing other refractory bricks. Specific advantages include:

Extremely low contamination: Causes minimal defects such as stones and bubbles in molten glass, effectively ensuring the quality and purity of finished glass products.

Outstanding corrosion resistance: The incorporation of zirconia (ZrO₂) significantly enhances the brick's resistance to high-temperature glass melt and alkali vapors, extending furnace lifespan.

High mechanical strength and wear resistance: The electric melting process yields an exceptionally dense structure with high mechanical strength, enabling it to withstand mechanical impact and material erosion.

Superior high-temperature performance: Refractoriness exceeds 1750°C, maintaining structural stability at elevated temperatures.

When selecting AZS bricks, the following key indicators are crucial:

Chemical Composition:
Particularly zirconia (ZrO₂) content, which directly determines erosion resistance. Common grades include 33% (AZS-33), 36% (AZS-36), and 41% (AZS-41).

Bulk Density: Typically exceeds 3.5 g/cm³. Higher density indicates a denser structure, enhancing resistance to permeation and erosion.

Apparent Porosity: Generally below 5%. Low porosity effectively prevents glass melt and corrosive gases from penetrating the brick interior.

Room Temperature Compressive Strength: Extremely high, typically exceeding 150 MPa, ensuring sufficient mechanical strength.

Refractoriness: Typically exceeds 1790°C.

We recommend evaluating these parameters based on specific application conditions (e.g., temperature, glass type, erosion intensity). Our technical sales team can provide detailed product data sheets and assist with selection.

The primary distinction among these grades lies in their zirconia content and the corresponding performance enhancements:

AZS-33: The standard grade, offering excellent overall performance and high cost-effectiveness. Widely used in relatively less corrosive areas of glass melting furnaces, such as the tank bottom, upper structure, and feed channels.

AZS-36: High-zirconia grade with significantly superior resistance to molten glass erosion compared to AZS-33. The preferred material for the most critical and severely eroded areas such as float glass and bottle/jar glass furnace pool walls, offering extended service life.

AZS-41: Ultra-high zirconia grade with ultimate corrosion resistance. Typically used for melting specialty glass (e.g., electronic glass, borosilicate glass) or in extremely harsh environments like melt channels.

The selection principle is “allocation based on need.” Use the highest grade AZS bricks in areas with the most severe corrosion, and employ more economical grades elsewhere to achieve optimal cost-effectiveness.

Yes, a reliable AZS brick supplier should provide comprehensive technical support, including but not limited to:

Technical Consultation and Selection Recommendations: Based on your kiln drawings and process conditions, we recommend the most suitable AZS brick grades and masonry solutions.

Customized Product Processing: We can perform precise pre-processing and grinding of AZS bricks according to your provided drawings, ensuring installation accuracy and efficiency on-site.

Masonry Guidance and Training: We provide detailed masonry construction manuals and can even dispatch technical personnel for on-site instruction and training.

After-Sales Support and Troubleshooting: We offer ongoing technical assistance during operation to help analyze and resolve any issues that may arise. We are committed to being your strategic partner, not merely a material supplier.

We control dimensions and appearance through precise electrofusion casting processes and rigorous post-processing:

Dimensional Tolerances: Our AZS bricks feature high dimensional accuracy, with tolerances typically maintained within ±1% to ±2mm (depending on brick type). For critical applications, we offer CNC-machined precision-ground products to ensure millimeter-level joint accuracy.

Appearance Quality: Each brick undergoes rigorous inspection to ensure the absence of cracks, shrinkage cavities, or impurities that could compromise performance. Minor surface roughness or cold-rolled layers that do not affect structural strength are permissible, as these represent normal manufacturing characteristics.

The production and use of modern AZS bricks are highly environmentally friendly:

Production Process: Our manufacturing facilities strictly adhere to environmental regulations, control emissions, and are committed to improving energy efficiency.

Usage Phase: AZS bricks are inherently inert materials that do not release harmful substances at high temperatures, ensuring the safety and purity of glass products.

Waste Disposal: Post-use AZS bricks pose no environmental pollution risks due to their stable chemical properties. Furthermore, they are extensively recycled. After crushing, they serve as high-quality aggregates for producing other types of refractory concrete or castables, enabling resource circulation and aligning with sustainable development principles.