Preparation of Lightweight Mullite-Anorthite Refractories by Different Routes

Mullite-anorthite as a kind of lightweight refractory combines the low thermal conductivity of anorthite and the excellent thermal properties of mullite. In this work, mullite beads and calcium aluminate cement was used as the main component and bonding agent. The lightweight mullite-anorthite refractory was prepared by difference routes including foaming method, addition of pore-forming agent and sacrificial template method. The phase composition, bulk density, apparent porosity and thermal conductivity of samples were compared. The results showed that anorthite formed as the consequence of the reaction of cement and mullite. Extra addition of foam, cornstarch and polyurethane sponge could decrease the bulk density of samples. The pore size of samples prepared by foaming method was the smallest. The apparent porosity of samples obtained by sacrificial template method was largest, but the thermal conductivity was the highest due to the open pores.