1. Raw Material Composition

• Lightweight Refractory Materials: These materials are primarily made from refractory clay, high-alumina bauxite, silica-based materials, and other additives such as foaming agents and binders. For example, lightweight high-alumina bricks are made from high-alumina clinker as aggregate, with substances that decompose at high temperatures to release gases, forming a porous structure after firing. These raw materials are rich in high-temperature-resistant oxides, ensuring excellent refractory performance.
• Insulation Materials: The raw materials for insulation materials are diverse. Mineral wool types, like rock wool and slag wool, are made from natural rocks such as basalt and diabase or metallurgical slag, which are melted at high temperatures and spun or blown into fibers. Organic insulation materials, like polystyrene foam boards, are made from polystyrene resin through a foaming process. The choice of raw materials leads to varying insulation mechanisms and properties.

2. Microstructure

• Lightweight Refractory Materials: These materials have a porous internal structure, with relatively uniform and well-connected pores. This design allows gases to diffuse moderately at high temperatures, reducing thermal stress. The pore walls are typically thicker and composed of high-temperature-resistant mineral crystals, ensuring both strength and structural stability under heat, including resistance to thermal shock.
• Insulation Materials: Like lightweight refractories, insulation materials also have a porous structure. However, the pore sizes and shapes vary widely, with many of the pores being closed. For example, polyurethane foam insulation is filled with tiny closed air bubbles, restricting air movement and greatly inhibiting heat conduction. This unique structure achieves excellent thermal insulation, while the pore walls remain thin and rely on the material’s chemical cross-linking structure to maintain mechanical strength.

3. Thermal Stability

• Lightweight Refractory Materials: These materials exhibit excellent thermal stability, able to withstand frequent temperature fluctuations without cracking or peeling. This property is due to their balanced mineral composition and microstructure, which allows the high-temperature and low-temperature phases to adapt to temperature changes, buffering the stresses caused by thermal expansion and contraction. For instance, lightweight refractory materials used in intermittent kilns can continue to function properly even after multiple heating and cooling cycles.
• Insulation Materials: In comparison, insulation materials generally have lower thermal stability, particularly organic ones. Rapid temperature changes can damage their internal structure, such as causing the bubbles in foam insulation materials to burst, leading to deformation and reduced thermal performance. As a result, they are best suited for environments with stable temperatures.

4. Environmental Impact

• Lightweight Refractory Materials: During production and use, the primary environmental concern is controlling dust emissions. Some products with special additives may have a slight risk of heavy metal volatilization, but when produced using advanced techniques and environmentally friendly raw materials, their environmental impact can be minimized. Moreover, if properly treated, waste can be recycled and reused in less demanding applications.
• Insulation Materials: Environmental concerns vary among insulation materials. Mineral wool products require careful energy consumption and dust control during manufacturing, and inhaling fiber dust can pose health risks. Organic insulation materials, such as polystyrene foam boards, release toxic gases when burned, and their non-biodegradable nature presents challenges for waste disposal. However, the development of biodegradable insulation materials is underway, providing more eco-friendly alternatives.

5. Cost and Price

• Lightweight Refractory Materials: Due to the use of specialized refractory raw materials and complex processing techniques, including high-temperature firing and precise formulation, the cost of lightweight refractory materials is relatively high. High-quality, high-temperature-resistant lightweight refractories require substantial investment in research and production, which is reflected in their price. These materials are commonly used in industries with stringent production requirements and high economic returns.
• Insulation Materials: The cost of insulation materials varies significantly. Mineral wool materials have competitive pricing due to large-scale industrial production, with costs influenced by raw material prices and production scale. Organic insulation materials such as low-end polystyrene foam boards are affordable, but higher-end, environmentally friendly options incur higher research and development costs, making them more expensive. In general, insulation materials used in the construction industry prioritize cost-effectiveness while still meeting basic insulation requirements, making them more affordable than lightweight refractory materials.