Dry granulation of blast furnace slag shows high potential for saving energy and resources in comparison to conventional wet granulation. This thesis is about construction and further improvement of a rig for dry slag granulation (DSG) on laboratory scale. In the theoretical part the physical properties of blast furnace slag are considered in detail. Several models for calculation of viscosity, density and surface tension are compared in their applicability. An overview on current research work on DSG is also given. The practical part comprises preliminary tests and a mathematical simulation of the outflow of the slag from the melting crucible. The granulation tests performed with the DSG rig are described in detail. For optimum results, when using the reference slag and a disk diameter of 34 mm, the rotational speed should be 1200-1300 rpm and the temperature of the slag when impinged on the disk should be > 1400 °C.