Refractory metals are often used in alloys to improve the mechanical properties at high temperatures. However molybdenum and niobium react with oxygen at relatively low temperatures compared to their melting temperatures, which limits their technical applications. This reactivity can be used for recycling of Mo Nb alloys due to sufficient partial pressures of molybdenum oxide at maintainable temperatures. Consequently this compound can be separated via the gas phase. The main topic of this study was to determine which process conditions have a positive effect on oxidation and sublimation of this material. Part one of the thesis comprises a literature review to find out the state of the art and to identify base values for the practical tests. The second part describes the executed pipe furnace and rotary kiln experiments. The third part of the thesis depicts the evaluation and analysis of the generated sample residues regarding oxidation time and residual molybdenum content by scanning electron microscopy. The experimental results were statistically analyzed and summarized in images and tables, in order to compare them to literature and expected values.