Development of Silica Aerogel Added Lightweight Ceramic Sanitaryware

This study investigates silica aerogel as a partial replacement for quartz in fine fire clay (FFC) ceramic sanitaryware bodies with the aim of reducing fired weight and improving wall-thickness formation during slip casting. Silica aerogel was incorporated into industrial FFC formulations at 0.55, 3.00, 5.00, 7.50 and 10.00 wt%. The slips were shaped by slip casting and fired at 1250oC. The compositions were evaluated in terms of slip litre weight, thixotropy, Ford cup efflux time, wall- thickness formation, fired weight reduction, shrinkage, water absorption, bending strength, thermal expansion, firing deformation, colour, XRD phase evolution and SEM morphology. Silica aerogel addition decreased the slip litre weight and increased wall-thickness formation, confirming its influence on casting behaviour. The fired weight reduction reached 28.30% in the composition containing 10 wt% silica aerogel. However, increasing silica aerogel content also increased water absorption and firing deformation and reduced fired bending strength. Thus, the highest addition level provided the maximum lightweighting effect, whereas inter-mediate additions gave a more favourable balance between weight reduction and technological performance. XRD results showed that replacing crystalline quartz with porous amorphous silica modified α -quartz and cristobalite poly morph evolution during firing. Overall, silica aerogel is a promising lightweighting additive for FFC sanitaryware bodies, provided that its content is optimized with respect to mechanical strength, water absorption and dimensional stability.