The aim of this work is to investigate the heating behavior of HBI/DRI under inert gas atmosphere and to describe the phenomenological characteristics. The company Saarstahl AG and the Chair of Ferrous Metallurgy (CoFM) performed several experiments for heating Hot Briquetted Iron (HBI). The previous experimental results have shown that further research is necessary to understand the heating behavior of HBI. These investigations were done in the context of this master thesis. For this purpose, already existing experimental results were evaluated, as well as heating experiments in a vertical retort on a laboratory scale were executed under different process conditions. Thereby also softening behavior, degradation behavior and sticking phenomena had to be considered. During the experiment, the produced amount of CO and CO2 was measured by gas analysis. This was necessary to calculate the amount of oxygen and carbon and for comparing the results with the chemical analyses. The HBI-samples were analyzed metallographically by secondary electron microscopy (SEM) and electron probe micro analysis to obtain a better understanding of the occurring phenomena. This work provides the theoretical fundamentals and attempts to describe the observed results and phenomena.