Effects of ammonium molybdate additive and sintering temperature on the properties of foam ceramics based on ceramic tile polishing waste

Abstract

In this study, the foam ceramics based on ceramic tile polishing waste (CTPW) were successfully prepared by a simple solid phase sintering method. The CTPW was used as the main raw material, SiC inside CTPW as the foam agent and (NH4)6Mo7O24 as the sintering additive. Effects of the amounts addition of (NH4)6Mo7O24 (06 wt %) and sintering temperature (10801200°C) on the sintering properties, structural evolution, phase composition and mechanical properties have been investigated. During the sintering process, the SiC inside CTPW could react with oxygen and then produce the gases such as CO and CO2, which caused a closed-pore structure. After adding (NH4)6Mo7O24 and increasing the sintering temperature, a better porous structure with suitable pore size and high compressive strength could be obtained. It was found that the foam ceramics doped with 2 wt % (NH4)6Mo7O24 and sintered at 1200°C for 30 min showed excellent properties: a low bulk density (0.362 g/cm3), the appropriate pore size (0.94 mm), a uniform pore size distribution and a very high compressive strength (8.16 MPa).