the gases 22 23 for the post combustion via appropriate actuation of the positioning and turning mechanisms 40 41 43 this preferably occurs in such a way that local overheating of the surface of the scrap to greater than 90 of the melting point of iron oxide is not reached in any post combustion plane or post combustion sector and that the degree of post combustion of the exhaust gas emerging from the melting vessel is approximately 100 in addition to the inlets 21 in the interior shaft 5 inlets 42 are arranged in the wall 7 of the melting vessel 4 and are connected to feed lines for post combustion gases 22 in this regard the planes e 1 e 2 and e 3 e 4 formed by the interior shaft inlets 21 and the vessel wall inlets 42 respectively are offset relative to each other so that a post combustion plane with inlets 42 from the outside of the vessel and a post combustion plane with inlets 21 from the inside of the interior shaft 5 alternate from bottom to top the amount by which they are offset is up to 50 of the distance between the planes of the inlets this offset.