Das Projekt "Erforschung des Verhaltens von Chlor und Basen in Hochofenschlacke bezueglich der Faehigkeit zur Basenrueckhaltung" wird vom Umweltbundesamt gefördert und von Aktien-Gesellschaft der Dillinger Hüttenwerke durchgeführt. The aim of this project is to clarify the behaviour of chlorine in context with alkali within the blast furnace.The investigations involve possibilities of circulation of chlorine in combination with alkalis within the blast furnace, alkali and chlorine removal via top gas, influ-ences of chlorine and alkalis on the properties of burdon and coke, optimisation of operational conditions to control the movement of chlorine and alkali in the blast furnace for utilisation of more primary and secondary materials.Further objectives are investigations of the alkali retention capacity of slag, of primary and final slag in a wide range of temperature, the softening and melting behaviour of different burden materials. Operational data of blast furnaces will be evaluated with regard to alkali retention capacities of slag. The results will be applied for improved alkali and sulphur control with respect to the blast furnace operation and slag utilisation.