Fabrication of Foamed Porous Ceramics from Mixtures of Pork Bone and Incinerated Sewage Sludge Ash

Abstract

Ultra-lightweight ceramics were fabricated by firing the mixtures of pork bone (PB) and incinerated ash of sewage sludge. PB content in the mixtures was varied from 0 to 15 mass%. The mixtures were pressed in a discus body (4 cm in diameter) and the body was fired at the temperature range from 1000 to 1150°C for 1 h in air. Bloating behaviors were observed in the samples fired at the temperature over 1050°C. The remarkable lightweight ceramics, which have the apparent porosity less than 1.0 g cm⁻³, were obtained by the addition of 10–15 mass% PB and the firing at the temperature over 1050°C. Diffuse reflectance spectra revealed that ferric oxide in the samples fired at the temperature over 1050°C was reduced to ferrous oxide. It was considered that the large bloating in the PB added samples occurred due to both the evolution of oxygen from ferric oxide and the oxidation of residual carbon derived from PB inside the samples after melting of the surface at high temperatures.