Silica Brick

Silica bricks, made primarily from high-purity silica (SiO₂), are among the most critical refractory materials used in high-temperature industrial processes. With exceptional thermal stability, low thermal expansion, chemical resistance, and long service life, silica bricks are widely used in industries such as steel, glass, ceramics, cement, non-ferrous metals, and petrochemical processing.

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Silica Brick Product Property

Item		ZJAS-1680	ZJAS-1650	ZJAS-1550
Chemical composition（%）	Al2O3	≥65	≥63	≥60
	SiC+SiO2	≥30	≥30	≥30
Volume density（g/cm3)		≥2.65	≥2.60	≥2.50
Apparent porosity（%）		≤16	≤17	≤18
Compressive strength at room temperature（MPa)		≥90	≥90	≥80
Load softening temperature（℃）（0.2MPa,tO.6)		≥1680	≥1650	≥1550
Thermal shock stabilit（次）（1100℃，water cooling）		≥15	≥15	≥15
Wear resistance coefficient（A/C)		≤6	≤7	≤8

1. What Are Silica Bricks?

Silica bricks, also known as silica refractory bricks, are manufactured from high-purity quartz sand through a process of firing at extremely high temperatures. The resulting bricks are dense, crystalline, and highly resistant to heat and chemical attack.

Key characteristics include:

High temperature resistance: up to 1600–1700°C
Low thermal expansion: minimizing cracking in cyclic heating
Resistance to acidic slags and fumes
Mechanical strength under load
Energy efficiency: low heat loss due to dense structure

Silica bricks are primarily used in areas of industrial furnaces where temperatures are extremely high and chemical exposure is frequent, such as furnace roofs, walls, regenerators, and glass tank crowns.

2. Material Properties That Determine Their Uses

Silica bricks are chosen for their unique combination of physical, chemical, and thermal properties. Understanding these is essential for selecting the right brick for each industrial application.

Property	Definition	Impact on Industrial Use
Refractoriness	The temperature at which the brick softens	Determines maximum service temperature in furnaces
Load Softening Temperature	Temperature at which the brick can carry mechanical load without deformation	Critical for structural zones like furnace roofs
Thermal Expansion	Degree of expansion under heat	Low expansion prevents cracks during temperature cycling
Apparent Porosity	Volume of voids in the brick	Lower porosity increases chemical and slag resistance
Bulk Density	Mass per unit volume	Determines mechanical strength and thermal conductivity

By selecting silica bricks with appropriate specifications, industries can ensure optimal furnace performance and reduced maintenance costs.

3. Core Uses of Silica Bricks by Industry

Silica bricks are applied across various industries that require high-temperature, high-durability materials.

3.1 Steel Industry

Silica bricks are commonly used in:

Blast furnace roofs and walls
Hot blast stove checker chambers
Reheating furnace linings

Advantages in Steel Applications:

Withstand temperatures exceeding 1500°C
Resist molten metal corrosion
Maintain structural integrity under mechanical and thermal loads
Reduce maintenance downtime and improve furnace efficiency

3.2 Glass Industry

In glass manufacturing, silica bricks are used for:

Glass tank crowns
Superstructure walls
Regenerator chambers

Benefits:

Tolerate high temperatures up to 1600°C
Low thermal expansion prevents cracking
Retain heat efficiently, reducing fuel consumption
Maintain uniform glass quality through stable furnace lining

3.3 Ceramics & Kilns

Silica bricks are widely used in:

Kiln roofs and walls
Kiln furniture and supports

Advantages:

Withstand rapid heating and cooling cycles
Provide uniform heat distribution
Reduce thermal stress on delicate ceramic products

3.4 Cement Industry

Applications include:

Rotary kiln linings
High-temperature zones exceeding 1400°C
Areas exposed to chemical reactions during clinker formation

Benefits:

Protect kiln structures from chemical corrosion
Improve energy efficiency
Extend service life of the refractory lining

3.5 Petrochemical Industry

Silica bricks are used in:

Hydrocarbon cracking furnaces
Reactor linings in chemical plants

Advantages:

High thermal stability
Resistance to acidic and corrosive environments
Maintain consistent performance under extreme temperatures

3.6 Non-Ferrous Metallurgy

Applications include:

Aluminum, copper, and zinc furnaces
Smelting chambers and ladles

Advantages:

Endure molten metal exposure
Resist thermal shock
Extend campaign life of furnaces

3.7 Heat Treatment Furnaces

Used in:

Hardening, annealing, and tempering operations

Benefits:

Uniform heat distribution
Rapid heating and cooling tolerance
High dimensional stability

3.8 Aerospace & Specialty Applications

Although less common, silica bricks are used in:

Thermal protection systems
Rocket engine chambers
High-temperature insulation for aerospace applications

Advantages:

Withstand extreme launch and re-entry temperatures
Maintain structural integrity under thermal and mechanical stress

4. Temperature Ranges and Performance Parameters

Silica bricks are consumable materials in industrial furnaces. Their service life depends on multiple factors, including operating temperature, load, chemical environment, and thermal cycling. Therefore, the figures below are reference ranges only. Actual lifetime will vary depending on the specific furnace conditions and customer usage scenarios.

Application Zone	Typical Temperature (°C)	Recommended Brick Type	Reference Service Life*
Steel furnace roof	1400–1550	High-purity silica	Months to a few years, depending on load and thermal cycling
Glass tank furnace	1500–1650	Silica brick	Months to a few years, depending on chemical exposure and temperature
Coke oven	1300–1450	Silica brick	Months to a few years, depending on operational intensity
Ceramic kiln	1000–1300	Silica brick	Months to a few years, depending on heating/cooling cycles
Cement rotary kiln	1400–1500	Silica brick	Months to a few years, depending on clinker chemistry and temperature
Petrochemical reactor	1200–1500	Silica brick	Months to a few years, depending on chemical exposure and temperature fluctuations
Non-ferrous metal furnace	1200–1450	Silica brick	Months to a few years, depending on slag and thermal load

* Note: Silica bricks are consumable items, and their actual service life should be evaluated based on the specific operating conditions of each customer. Different furnace zones, temperatures, and chemical exposures will affect longevity.

5. Where Silica Bricks Should NOT Be Used

Despite their high performance, silica bricks are not suitable for all industrial zones:

❌ Strongly alkaline zones – susceptible to chemical attack
❌ High thermal cycling zones – may crack under frequent heating and cooling
❌ Low-temperature insulation areas – energy efficiency better achieved with insulating bricks

Understanding limitations ensures longer service life and cost-effective operations.

6. Silica Bricks vs Other Refractory Materials

Feature	Silica Brick	High Alumina Brick	Fire Clay Brick
Maximum Temperature	1600–1700°C	1750°C	1450°C
Thermal Expansion	Very Low	Moderate	Moderate
Thermal Shock Resistance	High	High	Low
Acid Resistance	Excellent	Poor	Moderate
Industrial Applications	Steel, Glass, Petrochemical	Steel, Cement	Kilns, Boilers

7. Buying Considerations for Silica Bricks

When purchasing silica bricks, consider the following factors:

Dimensions and density – standard or custom sizes
Maximum service temperature – verify suitability for furnace zones
Quantity – bulk orders reduce unit cost
Supplier reliability – certifications, quality assurance, and technical support

Highland Refractory Solutions:

ISO-certified silica bricks
Custom sizes and temperature grades
Global delivery and technical support
Long-term durability and energy-efficient products

8. Frequently Asked Questions (FAQ)

Q1: What are silica bricks used for?
A: Silica bricks are used in high-temperature industrial applications including steel, glass, ceramics, cement, petrochemical, and non-ferrous metal furnaces due to their thermal stability, chemical resistance, and mechanical strength.

Q2: What temperature can silica bricks withstand?
A: Silica bricks typically operate at 1600–1700°C depending on purity and density.

Q3: Are silica bricks better than high alumina bricks?
A: Silica bricks excel in acidic zones and glass-facing areas, whereas high alumina bricks are more suitable for alkaline zones with higher temperature requirements.

Q4: Can silica bricks be customized?
A: Yes. Highland Refractory provides custom dimensions, densities, and temperature grades to meet specific industrial requirements.

Q5: Where should silica bricks not be used?
A: Avoid strongly alkaline zones, high thermal cycling areas, and low-temperature insulation regions where chemical attack or thermal stress may occur.