The goal of this diploma thesis is it to produce dense sintered mullite with more than 90 % mullite, 5-10 % glass and 1 % corundum. The bulk density should be at least 89 % of the true density of mullite and the open porosity should be kept below 1,5 %. From the selected raw materials the mixtures caoline and tabular alumina, andalusite and tabular alumina and quartz and tabular alumina were built. The amount of glass should be below 10 %, because this amount is an important criteria for the softening behaviour of refractories. Residual corundum reacts with quartz to mullite under volume expansion. Therefore, the amount of corundum should be less than 1 %. The mixture caoline tabular alumina showed the best results concerning sintering behaviour and mullitization. All mixtures showed too low bulk densities and too high open porosities. One third of the produced sintered mullites reached the target of 90 % mullite content, the content of glass was below 10 % in all cases. Performing an optimization, the value of bulk density could be increased and open porosity decreased.