Lightweight silica bricks, also known as silica insulation bricks, are lightweight refractory materials with a SiO₂ content exceeding 90% and a bulk density ranging from 0.9 to 1.1 g/cm³. These bricks share similar refractoriness and load softening temperatures with ordinary silica bricks of the same composition. However, due to their high porosity, their compressive strength, slag resistance, and corrosion resistance are inferior to standard silica bricks, while their thermal shock resistance is significantly improved.
Composition:
Lightweight silica bricks are typically made from crystalline quartzite. Combustible additives such as coke, anthracite, or sawdust are mixed into the raw materials to form a porous structure, or a gas-foaming method is employed. The manufacturing process is similar to that of ordinary silica bricks. Primarily used in kiln components that require thermal insulation or weight reduction without direct contact with molten materials, exposure to corrosive gases, or sudden temperature changes. When used at high temperatures, it should not come into contact with alkaline refractory materials. Depending on the material composition, the maximum service temperature ranges from 1200°C to 1550°C.
Applications:
1. Construction Industry
- Wall Insulation: Used as thermal insulation material for building exteriors, lightweight silica bricks reduce heat and cooling losses thanks to their low thermal conductivity, light weight, and low water absorption.
- Interior Insulation and Soundproofing: Ideal for partitions and soundproof panels due to excellent thermal and sound insulation properties.
- Refractory Linings: Applied in chimneys, furnace walls, and kiln walls for thermal insulation.
2. Metallurgical Industry
- Steelmaking: Used as refractory materials in blast furnaces, converters, and electric furnaces due to their high temperature resistance.
- Aluminum Electrolysis Cells: Serve as lining materials, offering strong corrosion resistance and extended cell lifespan.
3. Chemical Industry
- Petroleum and Chemical Storage Tanks: Serve as inner-wall insulation materials with excellent corrosion resistance and low thermal conductivity.
- Refinery Insulation: Enhance energy efficiency in internal structures of refinery units.
4. Energy Sector
- Boilers and Chimneys in Thermal Power Plants: Provide insulation for improved energy utilization efficiency.
- Solar Panels: Act as insulation materials for solar panels, increasing energy conversion efficiency.
Refractory and Metallurgical Applications:
- Long-term use under high-temperature conditions (1500–1550°C) where no direct contact with slag occurs, such as insulation material for the inner lining of large blast furnace hot blast stove arches and silica brick masonry in glass kilns.
- Direct flame contact, such as the roof of reheating furnaces for rolling mills.
- General industrial kiln insulation.
In summary, lightweight silica bricks are widely used in construction, metallurgy, chemical, and energy sectors due to their unique properties, making them an excellent choice for high-performance refractory and insulation materials.
