In glass production, zirconia bricks primarily play a dual role as a “protective barrier” and a “quality guardian.” Their specific applications vary depending on the zirconium oxide content and brick type performance, and they are precisely deployed in various key parts of the furnace:

Main Force: Fused Zirconia-Corundum Bricks (AZS bricks, ZrO₂ content 33%-45%)

This is the most widely used series of zirconia bricks. Its name AZS is derived from the first letters of its main components: alumina (A), zirconium oxide (Z), and silicon dioxide (S). Due to its excellent resistance to molten glass corrosion and low contamination of the molten glass, it is widely used in areas that come into direct contact with molten glass.

Core areas resisting high-temperature corrosion: Its performance and applications vary depending on the zirconium oxide content. AZS-33# has good castability and is commonly used in the upper structure of kilns and the walls of working tanks. AZS-36# offers better corrosion resistance and is suitable for tank wall areas with high glass flow rates or high temperatures. AZS-41# has the strongest corrosion resistance and is the preferred material for protecting the kiln’s “throat”—critical areas such as flow channels, charging port corners, and kiln sills—which often determine the lifespan of the entire kiln.

Ensuring Glass Purity: Through advanced processes such as oxidation melting, modern AZS bricks can reduce the carbon content to extremely low levels (e.g., 0.005%), significantly reducing contamination of the molten glass and effectively controlling bubble precipitation, preventing defects such as stones and bubbles in the glass. Latest technologies can even reduce the bubble precipitation rate to levels comparable to more expensive αβ alumina bricks, allowing for applications in the cooling and forming parts of high-end products such as electronic glass and photovoltaic glass.

Specialty Elite: High Zirconium Bricks (ZrO₂ content ≥ 89%)

For specialty glasses with extremely stringent quality requirements, high zirconium bricks with extremely high zirconium content are necessary. Its mineral phase is almost entirely composed of zircon, exhibiting extremely low contamination of the molten glass and excellent thermal shock resistance. Therefore, it is widely used in critical parts of furnaces in the production of specialty glasses such as television glass, borosilicate glass, aluminosilicate glass, and fiberglass.

In general, the main use of zirconium bricks in the glass industry is as “armor” for the melting furnace. AZS series bricks serve as the “conventional force” providing primary protection, while high zirconium bricks are the “special forces” protecting high-end specialty glass production lines.

Applications of zirconium bricks in the glass industry最先出现在Ruitailianxin。

Glass Industry Kilns (Core Application)

Glass melting furnaces are the most widely used application of zirconium bricks, accounting for over 90%. Based on the ZrO₂ content, different types of zirconium bricks are precisely used in key parts of the kiln:

AZS-33# bricks (ZrO₂ approximately 33%): Good castability, mainly used in the upper structure of the kiln, working pool walls, and material channels—areas where there is no direct contact or less erosion.

AZS-36# bricks (ZrO₂ approximately 36%): Superior erosion resistance, suitable for hot spots with high glass flow rates and temperatures, such as the walls of the molten glass pool.

AZS-41# brick (ZrO₂ approximately 41%): Offers the best corrosion resistance among zirconium-corundum bricks, used in the most critical parts of the kiln, such as flow channels, kiln sills, and feed inlet corners.

High-zirconium brick (ZrO₂ > 80%): Exceeds AZS-41# in performance, exhibiting extremely low corrosion rates above 1600℃. Used in critical parts such as the walls and flow channels of long-life kilns in high-end production lines for photovoltaic glass and LCD glass, with a service life several times that of traditional materials.

Special High-Temperature Treatment Kilns

Fly Ash Vitrification Electrofusion Kilns: When processing waste incineration fly ash, traditional materials are easily corroded by CaO and chloride ions. Electrofused Z80 high-zirconium bricks exhibit excellent corrosion resistance (corrosion rate of only 0.6 mm/month, far superior to AZS bricks’ 1.6 mm/month), making them ideal for such demanding conditions.

Electronic and Specialty Glass Furnaces: High-zirconium bricks, due to their extremely low contamination of molten glass and near-zero bubble formation rate, are used in production lines for high-quality glass such as LCD glass and borosilicate glass.

Other Industrial Furnaces

Steel and Iron Metallurgy: Used in ladle slides, RH furnace immersion tubes, etc., to resist erosion and corrosion from molten steel.

Chemical Industry: As linings for coal gasification furnaces, resistant to acidic media and high-pressure environments.

Non-ferrous Smelting: Used as lining material in some high-temperature, highly corrosive areas.

Zirconium bricks are mainly used in which kilns?最先出现在Ruitailianxin。

The core applications of zircon bricks are concentrated in the following areas:

1. Glass Industry (Core Application)

This is the most important and widespread application area for zircon bricks. Different types of zircon bricks serve different parts of glass furnaces.

Critical parts that come into direct contact with molten glass: such as the walls of the melting pool, bottom lining bricks, and flow channels. These parts must withstand the intense scouring and chemical erosion of high-temperature molten glass. Fused zirconia-corundum bricks (AZS bricks) and dense zircon bricks, due to their extremely low apparent porosity and excellent erosion resistance, have become the standard choice for these applications. For example, models like AZS-33# and AZS-41# are common products categorized based on their zirconium oxide content.

Upper part of the kiln and areas experiencing temperature fluctuations: such as the breast wall and regenerator partition walls. Although these parts do not directly contact the molten glass, they must withstand high temperatures, flame erosion, and the corrosion of alkaline volatiles. Sintered zircon-corundum bricks or zircon bricks are commonly used in these applications due to their superior thermal shock resistance.

Specialty glass and environmental protection fields: In the production of high-quality glass such as electronic glass and photovoltaic glass, AZS fused bricks with ultra-low bubble precipitation rates are used to prevent bubble contamination of the molten glass. Furthermore, in environmental projects such as the vitrification of fly ash from waste incineration, high-zirconium bricks (approximately 80% ZrO₂ content) effectively extend the kiln’s lifespan due to their significantly superior corrosion resistance compared to ordinary AZS bricks (the corrosion rate is only about one-third that of AZS-41# bricks).

2. Iron and Steel Metallurgical Industry

In the iron and steel industry, zircon bricks are mainly used as linings for steel ladles, especially in areas directly impacted by molten steel and in the slag line region. These areas need to withstand the intense scouring and chemical corrosion of molten steel and slag, and zircon bricks can significantly improve the service life of the ladle.

3. Other High-Temperature and Wear-Resistant Applications

Chemical Furnaces: Utilizing their excellent chemical stability, they are used to resist corrosion from various acidic and alkaline media and solutions.

Wear-Resistant Equipment: Zirconium oxide bricks (with extremely high ZrO₂ content) are often used as linings for the cylinders of equipment such as ball mills due to their excellent wear resistance.

In summary, the application of zircon bricks closely revolves around the three keywords “high temperature,” “corrosion,” and “wear,” making them a key material for ensuring the long-term, stable operation of many high-temperature industrial processes.

What industries are zircon bricks mainly used in?最先出现在Ruitailianxin。

I. Classification by Production Process

This is the most basic classification method, determining the material’s fundamental properties.

Fused Cast Zircon Bricks: These are made by melting the raw materials in an electric arc furnace and then casting them. They have a dense structure and extremely strong erosion resistance. The most typical example is fused cast zircon-corundum brick (AZS brick), commonly graded AZS-33#, 36#, 41#, etc., based on ZrO₂ content; higher content results in better erosion resistance.

Sintered Zircon Bricks: These are made by crushing, molding, and sintering the raw materials at high temperatures. Their porosity is usually higher than fused cast bricks. Common types include sintered zircon bricks and sintered zircon-corundum bricks, mainly used in contact with molten glass or as a transition layer material.

II. Classification by Chemical Composition and Mineral Structure

This is the most fundamental classification basis in the industry.

Zircon Bricks: Primarily composed of zircon (ZrSiO₄), with a ZrO₂ content typically around 65%. They exhibit good resistance to acidic slag and low-alkali glass, and are commonly used for steel ladle linings and the upper structure of glass kilns.

Zircon-Corundum Bricks (AZS): Belonging to the Al₂O₃-ZrO₂-SiO₂ ternary system, the main minerals are corundum and zircon. Based on the production process, they are further divided into fused cast zircon-corundum bricks and sintered zircon-corundum bricks, and are core materials for critical components such as glass kiln walls and flow channels.

Zirconium Oxide Bricks: Extremely high ZrO₂ content (usually above 90%), exhibiting outstanding high-temperature resistance and erosion resistance, used in the most demanding operating conditions.

III. Classification by Application Area

Zircon bricks for glass furnaces: These have the largest usage, encompassing the AZS series and dense zircon bricks mentioned above, used in melting pools, working pools, and feed channels.

Zircon-containing bricks for metallurgy: These include alumina-zirconium-carbon and zirconium-carbon sliding nozzle bricks, stopper rods, etc., utilizing their thermal shock resistance and erosion resistance.

In general, the classification of zircon bricks is based on two main lines: production process and chemical composition. Different classifications directly determine their application scenarios and service life.

Classification of zircon bricks最先出现在Ruitailianxin。

1. Excellent High-Temperature Resistance

Corundum bricks possess extremely high refractoriness, typically reaching 1750℃ to 1830℃. Their load-bearing softening initiation temperature is also generally higher than 1700℃. This means that they maintain structural stability even at high temperatures close to their melting point (2050℃), resisting softening and deformation, making them ideal lining materials for various ultra-high-temperature kilns.

2. Outstanding Mechanical Properties and Erosion Resistance

Corundum bricks have high mechanical strength, with a maximum compressive strength of 340MPa at room temperature, and some high-purity products exceeding 100MPa. Simultaneously, their extreme hardness (Mohs hardness of 9, second only to diamond) provides excellent wear resistance, effectively resisting the erosion of high-speed airflow and materials. Furthermore, its dense structure and low porosity effectively block the penetration and erosion of molten slag, molten metal, and molten glass, exhibiting extremely high chemical stability.

3. Performance Shortcomings and Optimization

Despite its excellent performance, dense corundum bricks have relatively poor thermal shock resistance (the ability to resist rapid temperature changes without cracking), which is its main weakness. To improve this property and enhance erosion resistance, industrial applications often optimize this by introducing additives such as ZrO₂ (zirconium corundum brick) or Cr₂O₃ (chromium corundum brick). For example, adding an appropriate amount of Cr₂O₃ can significantly improve the material’s resistance to molten slag erosion and thermal shock resistance while maintaining high-temperature resistance.

4. Key Application Areas

Based on the above properties, corundum bricks are widely used as working linings in equipment such as blast furnaces, ladle refining furnaces, glass melting furnaces, petrochemical gasification furnaces, and carbon black reactors, significantly extending equipment life and ensuring stable production operation.

Performance of corundum bricks最先出现在Ruitailianxin。

I. Strictly Control Thermal Shock and Temperature Fluctuations

Corundum bricks have poor thermal shock stability and limited resistance to rapid temperature fluctuations. During kiln baking and operation, drastic temperature changes should be avoided, especially in the 900-1150℃ range. The heating or cooling rate should generally not exceed 15℃/h to prevent cracking or even shattering of the bricks due to crystal transformation. In areas with frequent temperature fluctuations (such as the charging port), it is recommended to use other brick materials for external protection.

II. Proper Construction and Avoidance of Eutectic Reactions

The chemical compatibility between different refractory materials must be considered during construction. For example, fused cast zirconia corundum bricks and clay bricks may eutecticly fuse when in contact at temperatures above 1300℃; direct contact should be avoided during construction. Furthermore, for bricks with casting shrinkage cavities, the shrinkage cavities should be oriented towards the inside of the kiln when constructing the walls of the melting chamber to prevent material leakage due to erosion.

III. Consider the Influence of Chemical Erosion and Atmosphere

While corundum bricks have strong resistance to acid and alkali erosion, certain conditions still require attention. For example, fused zirconia corundum bricks produced under a reducing atmosphere have a higher carbon content, which significantly reduces their resistance to molten glass erosion, making them prone to contaminating the molten glass and generating bubbles. High-quality bricks produced by the oxidation method should be prioritized. Additionally, chromium corundum bricks with an appropriate amount of Cr₂O₃ exhibit superior performance in resisting slag penetration and chemical erosion compared to ordinary corundum bricks, making them suitable for more demanding conditions.

IV. Optimize Raw Materials to Enhance Overall Performance

The choice of raw materials for corundum bricks directly affects their performance. Studies show that corundum bricks using tabular corundum as aggregate outperform similar products using fused white corundum as aggregate in terms of density, strength, wear resistance, and slag penetration resistance. Therefore, high-quality tabular corundum-based bricks should be given priority in key areas to achieve a longer service life.

What issues need attention when using corundum bricks in kilns?最先出现在Ruitailianxin。

In the field of electronic ceramic sintering, corundum fire bricks are used for the lining of furnace walls, arches, and flues in the high-temperature sections of pusher kilns, roller kilns, and atmosphere tunnel kilns. They are suitable for firing piezoelectric ceramics, chip capacitors, resistance ceramics, and filter ceramic components. Their low-iron and low-alkali properties prevent impurities from precipitating and contaminating the ceramic body at high temperatures, ensuring the stability of electrical parameters such as dielectric constant and insulation resistance of components. When used with corundum-based firing plates and sagger bases, they prevent the green bodies from sticking together and interpenetrating elements, improving the yield of finished products.

In magnetic material production, high-purity corundum fire bricks are commonly used in the high-temperature zones of ferrite core and permanent magnet sintering furnaces. This resists corrosion from alkali metal volatiles during sintering, resists corrosion from reducing atmospheres, maintains its shape under long-term high-temperature loads, and prevents lining debris from contaminating the magnetic material, ensuring consistent magnetic properties such as permeability and coercivity.

In semiconductor and photovoltaic electronics, dense corundum fire bricks are used as linings in monocrystalline silicon and sapphire crystal growth furnaces, wafer annealing furnaces, and chip packaging atmosphere furnaces to meet ultra-high purity requirements and prevent impurities from contaminating silicon-based materials. Corundum lining is used in high-temperature heat treatment furnace chambers to withstand special atmospheres such as nitrogen and hydrogen, maintaining uniform and stable furnace temperature and ensuring the precision of chip annealing and oxidation processes.

In the field of lithium-ion battery new energy electronic materials, corundum bricks are used in the high-temperature section linings of ternary and lithium iron phosphate cathode material sintering kilns to prevent iron and calcium impurities from penetrating into the electrode powder and to prevent the degradation of battery electrochemical performance. Meanwhile, corundum fire bricks can be used to manufacture thermocouple protective sheaths and high-temperature insulating components. Leveraging their excellent insulation properties under high frequency and high voltage, they are suitable for high-temperature insulation protection of electronic equipment.

Overall, corundum fire bricks, with their advantages of high temperature resistance, corrosion resistance, and high purity, have become an indispensable refractory base material for stable mass production in high-end electronics manufacturing.

Applications of corundum fire bricks in the electronics industry最先出现在Ruitailianxin。

In specific production processes, corundum bricks are mainly used in the following areas:

Core Refractory Material for Tunnel Kilns and Roller Kilns

As the working layer lining of these continuous kilns, corundum bricks are in direct contact with the flame, resisting the severe thermal shock and chemical erosion of the high-temperature firing zone, ensuring the long-term stable operation of the kiln. In high-voltage electrical porcelain firing tunnel kilns and building material roller kilns, lightweight corundum bricks are also used as direct-fired layer linings, combining high-temperature resistance and energy-saving effects.

High-Temperature Load-Bearing and Support Components

Utilizing its high strength and excellent high-temperature volume stability, corundum bricks are used to manufacture kiln furniture such as kiln car roof panels, columns, and beams to support and bear the ceramic products to be fired, ensuring they do not deform at high temperatures.

Specialty Ceramics and Electronic Ceramics Firing

For specialty ceramics and electronic ceramics requiring high purity, corundum bricks can be used as linings for firing furnaces. Their high purity effectively prevents product contamination at high temperatures.

For more demanding applications, zirconium corundum bricks, which incorporate zirconium oxide into corundum, are used. Their erosion resistance and thermal shock resistance are further enhanced, and they are often used in highly eroded areas such as the discharge port of ceramic frit glaze kilns.

Applications of corundum bricks in the ceramic industry最先出现在Ruitailianxin。

1. Linings for synthetic ammonia converters and coal gasification furnaces

First-stage and second-stage converters withstand long-term high-temperature, high-pressure, and strong reducing gas flows at 1300-1450℃. High-purity corundum bricks resist hydrocarbon and water vapor erosion, preventing lining spalling and gas leakage. Chromium corundum bricks are used as the working layer in coal-water slurry and slag-oil gasification furnaces to resist the erosion of high-temperature molten slag and high-speed gas flows, reducing the frequency of unplanned unit shutdowns.

2. Radiation section, furnace bottom, and furnace tube support for ethylene cracking furnaces

The temperature in the radiation zone of the cracking furnace is 1000-1250℃, and the flue gas contains sulfides and hydrocarbon media. Corundum-mullite bricks possess both high-temperature resistance and thermal shock resistance. Used in furnace walls, furnace bottoms, and irregularly shaped support bricks, they protect furnace tubes from high-temperature deformation and media corrosion, ensuring stable pyrolysis reactions.

3. Wear-resistant lining for catalytic cracking cyclone separators and flues

Oil and gas carrying catalyst particles erode the inner walls of equipment at high speeds. Corundum bricks, with their high Mohs hardness and wear resistance far exceeding high-alumina and clay bricks, are used in separator cones, inclined tubes, and high-temperature flue bends to reduce wear and perforation, extending equipment lifespan.

4. Lining for high-temperature sections of carbon black reactors and heating furnaces

The reaction zone of carbon black furnaces experiences extremely high temperatures and highly corrosive acidic flue gas. Corundum bricks, with their strong chemical stability, are not easily reacted with the media. In various tubular heating furnaces, corundum bricks are used to line the high-temperature furnace chamber and burner perimeter to isolate the high-temperature flame and prevent ordinary refractory materials from softening and cracking.

Compared to ordinary refractory bricks, corundum bricks are suitable for the complex high-temperature and corrosive environment of petrochemical plants. Although the cost is relatively high, the overall operation and maintenance cost is lower over a long period of operation. They are an indispensable high-temperature refractory material for modern large-scale refining and fertilizer plants.

Applications of corundum bricks in the petrochemical industry最先出现在Ruitailianxin。

In the steel industry, corundum bricks are the preferred lining material for many core equipment components. They are used to construct high-temperature, high-pressure, and severely eroded areas such as the blast furnace belly and tuyeres, as well as the regenerators of hot blast stoves, capable of withstanding temperatures above 1750℃ and intense airflow. In converters, electric arc furnaces, and ladle refining furnaces (such as LF and VD furnaces), the excellent slag erosion resistance and molten steel penetration resistance of corundum bricks effectively resist the chemical erosion of high-temperature molten slag, preventing steel contamination and significantly improving steel purity and equipment lifespan. Furthermore, key functional components in continuous casting processes, such as sliding gate nozzles and permeable bricks, also frequently utilize corundum materials, leveraging their high strength and high thermal shock resistance to achieve precise control of molten steel flow rate.

In the non-ferrous metal smelting field, corundum bricks also perform exceptionally well. For example, in aluminum electrolysis cells, it serves as a lining material that resists the severe corrosion from high-temperature cryolite molten salt and liquid aluminum. In flash smelting furnaces for heavy metals such as copper and zinc, it also effectively resists the scouring and chemical corrosion of high-FeO slag.

In summary, corundum bricks, with their stable chemical properties at extreme high temperatures, high strength, and corrosion resistance, comprehensively safeguard the entire metallurgical process from ironmaking and steelmaking to continuous casting and non-ferrous smelting, acting as “high-temperature guardians” to ensure production efficiency and product quality.

Applications of corundum bricks in the metallurgical industry最先出现在Ruitailianxin。