The kaolin beneficiation industries produce waste that is rich in Al2O3 and SiO2, oxides that when sintered at high temperatures react to form mullite. Due to the rare occurrence of the mullite mineral in nature, the number of studies in order to obtain it has been growing in recent years due to its properties excellent. This study aims to examine the feasibility of the use of microwave energy as an alternative to synthesize mullite from kaolin residue, since the use of microwave energy in the synthesis of materials has gained importance for the speed and economy when compared to conventional methods. The compositions studied (residual kaolin + alumina) were established according to the stoichiometry of mullite. The samples were sintered in a microwave oven home changed, varying power and time. It was observed that with the increase of these variables the intensity of the peaks of the mullite phase increased.