Manufacturing ceramic foams from granite sludge

In this study, ceramic foams were manufactured by using granite sludge as the principal material, red mud as the additive and SiC as the foaming agent, and the effects of different granite sludge-to-red mud mass ratios, firing temperatures and foaming agent content on the bulk density, porosity, mechanical properties and thermal conductivity of the foams were systematically investigated. The addition of 5-15 wt % red mud produced foams with well-distributed pores that possessed different dimensions and thus improved their physical and mechanical properties. A close correlation was found between the firing temperature, foaming agent content, and the pore structures and properties of foams based on the degree of matching between liquid phase generation and gas emission. The optimal conditions for preparing the ceramic foams were 10 wt % red mud and 1.0 wt % SiC at 1150 degrees C. The corresponding foam had a low bulk density of 296 << 38 kg/m3, a considerable compressive strength of 2.75 << 0.41 MPa and a low thermal conductivity of 0.061 << 0.010 W/(m<middle dot>K), exhibiting good prospects for applications in the building and construction sector.