The early pyrolyse of organic clay additives due to the counter flow of hot gas and clay causes a high emission of volatile hydrocarbons during expanding clay production. Aiming to improve the off – gas emission there is a research on the suitability of different substances as alternative clay additive. Based on the results of clay expanding tests and thermo gravimetric analyses connected with a mass spectrometer, molasses could be carried out as an environmental harmless clay additive of high potential. Furthermore this thesis is focused on the investigation of the firing atmosphere of the rotary kiln. Reduction of excess air is regarded as key parameter for development of an innovative process management accompanied by the optimization of the energetic process efficiency. The basis is provided by a material and energy balance of this plant section, to record the actual operating conditions and to estimate potential optimizing measures. In addition the heat transfer in the firing atmosphere caused by increased concentrations of carbon dioxide and water based on intensified gas radiation is studied. Initial rough calculations and clay expanding tests with various water atmospheres showed significant indicates of an intensified heat transfer.