Rongsheng Refractories manufactures high-alumina lightweight bricks designed for tunnel kilns; they offer excellent thermal insulation and energy savings, feature high resistance to heat and corrosion, and ensure a long service life.
Insulating Refractory Material: Lightweight High-Alumina Bricks
These lightweight high-alumina bricks are produced using high-quality high-alumina grog and high-purity clay, with polystyrene foam spheres added as pore-forming agents. During firing, the spheres burn away to create a porous structure, resulting in a lightweight brick with superior thermal insulation properties.
Features of Lightweight High-Alumina Refractory Bricks:
- High raw material purity.
- Uniform pore structure.
- Low thermal conductivity and low heat capacity.
- High strength and high dimensional accuracy.
Applications for Lightweight High-Alumina Refractory Bricks:
- Thermal insulation for various industrial kilns and furnaces.
- Linings for the preheating and cooling zones of tunnel kilns and roller kilns.
- Roller-hole bricks for roller kilns; linings for low- to medium-temperature resistance furnaces.
Lightweight High-Alumina Insulating Bricks
Lightweight high-alumina insulating bricks are typically produced using high-alumina bauxite clinker and a small amount of clay. After grinding, the mixture is cast and formed as a slurry using gas-generation or foaming methods, then fired at temperatures between 1300°C and 1500°C. Industrial alumina may sometimes be used to replace a portion of the bauxite clinker. These bricks are used for kiln linings and thermal insulation layers, as well as in areas not subject to severe erosion or scouring by high-temperature molten materials. When in direct contact with flames, the surface temperature of the brick must not exceed 1350°C.
The raw materials used for lightweight refractory materials are similar to those used for their dense counterparts, resulting in good high-temperature resistance; additionally, the presence of numerous tiny, closed pores within the material provides effective thermal insulation. There are three main methods for creating these pores: the combustible additive method, the foaming method, and the chemical method. Traditional lightweight refractory products include lightweight clay bricks, lightweight high-alumina bricks, and lightweight silica bricks. Modern varieties include lightweight synthetic mullite products, refractory fiber bulk and processed forms (such as folded modules and needled blankets), hollow alumina sphere products, and high-alumina or mullite lightweight sphere products.
“Lightweight bricks” generally refer to foamed bricks; these are commonly used for interior partition walls because they do not add excessive load to the floor structure while offering good sound insulation. High-strength products utilize high-quality tabular corundum and mullite as aggregates, with a sillimanite composite matrix, blended with special additives and small amounts of rare-earth oxides, followed by high-pressure forming and high-temperature firing. Common materials for lightweight insulating refractory bricks include clay-based types, high-strength high-alumina cenosphere bricks, low-iron mullite and high-alumina lightweight insulating bricks, and diatomite insulating bricks.
Advantages and Performance Characteristics of Lightweight High-Alumina Insulating Bricks
- Cost-effectiveness: Using these bricks can lower foundation costs, reduce the cross-sectional dimensions of structural frames, and save on steel and concrete, thereby significantly reducing the overall cost of the building. Compared to solid clay bricks, the use of lightweight bricks can lower the total construction cost by nearly 5% or more.
- Practicality: Lightweight bricks allow for increased usable floor area. Additionally, thanks to the excellent thermal insulation properties of the material, indoor temperatures during hot summers are 2–3°C lower than with solid clay bricks, leading to reduced electricity consumption for air conditioning.
- Constructability: Lightweight bricks offer excellent workability, making construction simple and convenient. Their large size and light weight reduce labor intensity, improve construction efficiency, and shorten the overall construction schedule.
