Porous mullite ceramics were prepared by foam-gelcasting and press-less sintering process, using sodium dodecyl sulfate and rosin soap as foaming agent and electric molten mullite powder as raw material. The properties (such as porosity, bulk density, compressive strength and thermal conductivity) of prepared materials were tested. With scanning electronic microscopy analysis, the effects of foaming agent variety and concentration on the microstructure and properties were studied. The foaming ability and foam stability of sodium dodecyl sulfate are the best compared with rosin soap and the properties of porous mullite ceramics using sodium dodecyl sulfate are also the best. Using sodium dodecyl sulfate as foaming agent, with the concentration increasing, the bulk density of the prepared ceramic gradually is reduced and the apparent porosity is gradually increased, the thermal conductivity is decreased, and the compressive strength is decreased too. Using sodium dodecyl sulfate as foaming agent, bulk density, open porosity, compressive strength and thermal conductivity of the prepared porous mullite ceramics is 0.24 similar to 0.57 g/cm(3), 89.13%similar to 92.85%, 0.51 similar to 4.54 MPa, and 0.06 similar to 0.17 W/(m.K), respectively.
