Research on the Application of Recrystallized Silicon Carbide in the Glass Industry

As the glass industry moves toward energy efficiency, high performance, and environmental sustainability, the demands on high-temperature refractory materials are becoming increasingly stringent. Glass melting furnaces operate under extremely harsh conditions—high temperatures, chemical corrosion, intense heat load, and severe thermal shocks. Traditional oxide-based refractories such as fused cast AZS, high-alumina bricks, and silica bricks are gradually falling short of the requirements of modern glass manufacturing. Recrystallized Silicon Carbide (RSiC), with its excellent high-temperature resistance, thermal shock stability, high thermal conductivity, and chemical inertness, has become an important material in critical areas of glass production equipment.

This article explores the key applications of RSiC in the glass industry, analyzes its performance in typical equipment components, and discusses the challenges it faces and future development trends.

1. Operating Conditions in the Glass Industry

Glass furnaces typically run continuously for years under extremely demanding conditions. The main environmental characteristics include:

Ultra-high temperatures: Glass melting occurs at 1450–1600°C, with some flame-exposed areas exceeding 1650°C;

Severe thermal shocks: Feeding ports and cooling zones frequently undergo rapid heating and cooling cycles;

Highly corrosive atmospheres: Vapors containing sulfur, alkalis, and volatile oxides (e.g., Na₂O, K₂O) chemically attack refractory linings;

Molten glass erosion and infiltration: Materials must be dense and non-reactive to prevent glass penetration;

Long-term continuous operation: Once started, the furnace cannot be shut down for maintenance for several years; therefore, materials must be exceptionally durable.

These challenges require refractories with excellent structural, thermal, and chemical performance.

2. Typical Applications of RSiC in the Glass Industry

3. Channel Lining Bricks

RSiC is widely used in the channel sections of glass furnaces as channel bricks or flow blocks. Its high thermal conductivity promotes uniform heating of the glass melt, while its low thermal expansion coefficient resists cracking due to thermal cycling. Compared to traditional high-alumina bricks, RSiC offers significantly longer service life and reduced maintenance requirements.

2. Feeding Port Zones

The feeding port is one of the most thermally stressed areas in the furnace. Thanks to its outstanding thermal shock resistance, RSiC can maintain structural integrity under rapid temperature fluctuations, preventing spalling or cracking due to frequent expansion and contraction.

3. Burner Blocks and Flame Space Components

In regenerative glass furnaces, RSiC is used to manufacture burner nozzles, flame arch bricks, and air-inlet plates. These components endure direct flame impingement and high-temperature gas flow. The material’s high hardness and thermal conductivity reduce surface temperature gradients, minimizing cracking and erosion.

4. Components in Contact with Molten Glass

Special-grade high-purity RSiC can also be applied in direct-contact areas with molten glass, such as overflows, launder channels, and spouts. Its dense structure and low reactivity help resist glass infiltration and chemical degradation, significantly extending service life in these sensitive areas.

3. Performance Advantages of RSiC in Glass Furnaces

Property	RSiC Performance
Maximum Operating Temperature	≥1800°C
Thermal Conductivity	25–35 W/m·K
Thermal Expansion Coefficient	~4.5×10⁻⁶/K
Thermal Shock Resistance	>100 cycles (ΔT ≥1000°C)
Alkali Resistance	Excellent
Oxidation Resistance	High-temperature stable

These properties make RSiC especially suitable for critical parts of the glass furnace where maintenance is difficult and operational continuity is vital.

4. Performance Feedback from Industrial Use

Feedback from multiple glass manufacturers has shown:

RSiC linings extend service life by 30–50%, with some applications doubling lifespan;

Furnace thermal efficiency improved by 2–4% due to better heat transfer;

Component failure rate significantly reduced thanks to better shock resistance;

In high-temperature corrosion zones (e.g., around the feeder and burners), RSiC exhibits lower deformation and spalling rates compared to traditional bricks.

5. Challenges and Development Trends

Despite its advantages, the application of RSiC in the glass industry still faces several challenges:

1. High Material Cost

The recrystallization process requires ultra-pure raw materials, precise particle size control, and high-temperature firing, resulting in significantly higher costs than common oxide refractories.

2. Size and Shape Limitations

Due to its high hardness after sintering, RSiC is difficult to machine. Producing large or complex-shaped components is expensive and time-consuming.

3. Oxidation in Molten Glass Contact Areas

In some cases, low-purity RSiC may oxidize in contact with molten glass, forming SiO₂ layers that can react with the melt. This can be mitigated by using high-purity RSiC and applying protective surface treatments.

Future development trends include:

Development of composite materials (e.g., RSiC + Si₃N₄, RSiC + Al₂O₃) to improve mechanical and chemical properties;

Use of 3D printing for customized or complex shapes, reducing lead time;

Exploration of Functionally Graded Materials (FGMs) to optimize corrosion-resistant and load-bearing zones within a single part;

Integrated design of refractories with furnace structures, improving reliability and service life.

6. Conclusion

Recrystallized Silicon Carbide, with its excellent thermal shock resistance, high-temperature strength, and corrosion resistance, has become increasingly important in the glass industry—particularly in areas subject to high thermal and chemical stress. With continued advancements in material processing and structural optimization, RSiC is expected to play a greater role in improving energy efficiency, reducing downtime, and supporting the high-quality development of modern glass manufacturing.

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