Nowadays it is increasingly important for European industry to perform their production processes not only in an effective but also in an efficient way, as the growing number of competitors from low wage countries is constantly lowering the sales price of products. In this thesis a rotary kiln for producing caustic calcinated magnesia, called CCM, was examined for potentials to increase the efficiency of the unit. The particular challenge of finding these potentials was that the year of construction and putting the rotary kiln into operation was 1912. To explore as many potentials for increasing the efficiency as possible, many different parameters of the kiln were recorded and measured for a period of four months. This made it possible to represent the oven with a detailed mass and energy balance and deduce optimization potentials based on it. These findings were analyzed for their benefit by using the balances and the feasibility was subsequently checked afterwards. The action list which has been created is presently being processed.