Pig iron production in the blast furnace is an energy consuming process, which leads to substantial CO2-emissions. National and international treaties push steel producers towards the continuing reduction of greenhouse gas emissions. Changes in the blast furnace process, which is the biggest CO2- emission source in the conventional steelmaking route, can help to lower the overall CO2-output of steel production considerably. Emission savings via a reduction of the coke consumption of the blast furnace as well as through improved process control are almost completely exploited in European blast furnaces. Further reductions of CO2-emissions are only possible by other means such as the use of pre-reduced material. In this thesis, possibilities to decrease CO2-output from the blast furnace, especially through the use of pre-reduced material in the form of direct reduced iron (DRI) or low reduced iron (LRI) with different degrees of metallization are depicted, furthermore, different processes for the production of DRI are described. Within the scope of this thesis, model calculations for various direct reduction processes were created, which were used to determine the specific CO2-emissions for the production of DRI depending on the degree of metallization of the products. The model calculations as well as the obtained results are presented.