Published: August 12, 2026 | Shenzhou | Reading time: 7 minutes

When a steel mill's continuous annealing furnace operates at 900°C, rock wool fails because its fibers soften; glass wool melts. When a petrochemical cracking furnace runs at 1,100°C, conventional insulation materials have already been eliminated from consideration. Ceramic wool — an alumina-silica fiber spun from molten kaolin clay and alumina at temperatures exceeding 1,800°C — maintains its fibrous structure and insulating performance at continuous operating temperatures up to 1,430°C. For furnace builders, kiln operators, petrochemical plant engineers, and power generation maintenance teams, ceramic wool is the only fibrous insulation material that operates in the temperature zone where other insulation materials physically cannot survive.

Ceramic Wool Temperature Grades

Product Formats: Blanket, Board, and Module

Ceramic wool is manufactured in three primary formats matched to installation method and application geometry. Ceramic wool blanket — the most common format — is a flexible, roll-form product available in standard thicknesses from 6mm to 50mm and densities from 64 to 160 kg/m³. Blanket is cut to size on-site and layered to achieve the required insulation thickness, typically secured with refractory anchors and washers. Ceramic wool board is a rigid, higher-density product manufactured by vacuum-forming ceramic fiber with a binder system, providing structural rigidity for self-supporting applications such as furnace door linings and hot face insulation that must maintain its shape under its own weight at temperature. Ceramic wool modules are pre-assembled blocks of folded blanket, compressed and mounted on a steel backing plate with an integral anchor system — these are installed in a grid pattern on furnace walls and roofs, providing faster installation than layered blanket with improved thermal performance through the compression-fit joint between adjacent modules that prevents heat leakage through seams.

Thermal Conductivity at Elevated Temperature

Ceramic wool's thermal conductivity behavior differs from building insulation materials in one critical respect: thermal conductivity increases significantly with temperature. At 200°C, ceramic wool blanket at 128 kg/m³ has a thermal conductivity of approximately 0.06 W/mK. At 600°C, this rises to approximately 0.15 W/mK. At 1000°C, it reaches approximately 0.28 W/mK — roughly four times the conductivity at low temperature. This temperature-dependent conductivity means that furnace insulation design requires an iterative calculation: the insulation thickness determines the cold-face temperature, which affects the mean insulation temperature, which determines the thermal conductivity, which affects the required thickness — and the calculation is repeated until the hot-face temperature, cold-face temperature, heat loss, and insulation thickness converge. This is fundamentally different from building insulation, where a single thermal conductivity value at 25°C mean temperature is adequate for design.

Shenzhou's ceramic wool manufacturing, supported by 40-plus years of thermal insulation experience and 100-plus certifications across 12 industrial parks, produces the full range of grades and formats for industrial high-temperature applications. The ceramic wool product line integrates with Shenzhou's complete insulation system — rock wool for applications below 650°C, glass wool for building and HVAC insulation, and aerogel for ultra-thin premium insulation where space constraints limit traditional insulation thickness.