In a process for granulating and comminuting molten material, the slag melt is acted upon by compressed water and discharged together with the vapour formed. The liquid slag is introduced into a granulation chamber in a free flowing jet while directing compressed water jets against the slag jet, whereupon the solidified and granulated slag is conducted through a pneumatic conveyor duct and a distributor along with the vapour formed. The partial streams leaving the distributor, via conically tapering nozzles are transferred into a grinding space exhibiting a lower pressure than the granulation space and from which the comminuted and solidified material is drawn off.