Designing Insulating Ceramic Foams for High-Temperature Furnace Lining*
1 FATEC Sertaozinho, Sertaozinho, SP/Brazil
2 Federal University of Sao Carlos, Materials Microstructure Engineering Group (GEMM), FIRE Associate Laboratory, Sao Carlos, SP/Brazil
3 WT Industria, Sao Carlos, SP/Brazil
Revision 26.08.2016, 30.10.2016
Volume 9, Issue 2, Pages 74 - 78
Abstract
The main reasons for using insulating ceramics as furnace linings are due to saving energy costs and environmental concerns. Traditional materials have high fused silica content to lower thermal expansion, absorb thermal radiation and enhance thermal shock resistance. However, silica migrates to surfaces under a reducing atmosphere, because solid SiO2 converts to SiO vapour. Commercial Al2O3–SiO2 and Al2O3–ZrO2–SiO2 linings present high porosity (70–85 vol.-%), but densify during use due to silica based binders. An alternative should be a plain Al2O3 insulating lining, but it presents low thermal shock performance and higher thermal conductivity. This work presents the design and application of Al2O3-based foamed lining refractories with low and stable thermal conductivity (0,25 W/m・K), high porosity (84 vol.-%), good compressive strength and high resistance to thermal shock. This material was applied as insulating lining in a glass melting furnace operating at 1700 °C. The proposed porous ceramic showed lower energy consumption when compared to commercial ones.
Keywords
furnace lining, porous ceramics, foams
References
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