refractories WORLDFORUM 9 (2017) [2] 1 PaPer Designing Insulating Ceramic Foams for High Tremperature Furnace Lining* V. R. Salvini, J. A. Rodrigues, W. T. Neto, V. C. Pandolfelli Fundamentals concerning thermal-optic properties of ceramic material are essential to point out the optimized pore size range where thermal insulation efficiency can be maximized [1]. The electromagnetic spectrum in Fig. 1 high- lights that the Infrared (IR) range comprises wavelengths (λ) from 0,7 μm to 1000 μm. 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 SiO 2 converts to SiO vapor. Commercial Al 2 O 3 –SiO 2 and Al 2 O 3 –ZrO 2 –SiO 2 linings present high porosity (70 to 85 vol-%), but densify during use due to silica based binders. An alternative should be a plain Al 2 O 3 insulating lining, but it presents low thermal shock performance and higher thermal conductivity. This work presents the design and application of Al 2 O 3 -based foamed lining refractories with low and stable thermal conductivity (0,25 W/mK), high porosity (84 vol-%), good compressive strength and high resistance to ther- mal 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. 1 Introduction The main purpose for using insulating ce- ramics as furnace lining is due to the energy costs and the environmental concerns. It is well known that thermal insulation capacity depends on engineered designed ceramic microstructures to reduce thermal energy conduction. Vânia R. Salvini FATEC Sertãozinho Sertãozinho, SP Brazil José A. Rodrigues, Victor C. Pandolfelli Federal University of São Carlos Materials Microstructure Engineering Group (GEMM), FIRE Associate Laboratory São Carlos, SP Brazil Waldemar T. Neto WT Indústria, São Carlos, SP Brazil Corresponding author: Victor C. Pandolfelli E-mail: vicpando@ufscar.br Keywords: furnace lining, porous ceramics, foams Received: 26.08.2016 Accepted: 30.10.2016 * The paper was awarded with the 1 st prize at ALAFAR 2016 Because the primary source of infrared is heat or thermal radiation, any matter with a temperature above absolute zero radiates in the infrared range [2]. This is caused by the vibration and rotation of atoms and/or molecules. The higher the temperature of an object, the more infrared energy is emitted. Considering the Infrared wavelengths, a good thermal insulating material must be able to reduce the intensity of radiation emitted within the temperature range of in- terest presented in Fig. 2. According to the literature [1, 3], there are two ways to reach this target: by adding substances which ab- sorb part of the radiation in the wavelength Fig. 1 Electromagnetic spectrum of energy highlighting Infrared radiation, where the shortwave (SW) corresponds to a range of 3–5 μm and longwave (LW) to 8–12 μm [2]