A process to separate steel-containing parts from a metal slag waste stream, comprising the following steps: the feed of a metal slag waste stream generated during steel production, particularly stainless steel or tool steel production; the dosed feed of the metal slag waste stream to a first high gradient magnet station, with the aid of a transport element; the pulling-out of steel-containing parts from the waste stream, through the action of the magnetic field generated by the first high gradient magnet station; the use of a breaking units to refine the steel-containing elements separated by the first high gradient magnet station, in a broken refined fraction, in which the steel-containing parts are at least partially freed of slag; the separation of the broken refined fraction at least into a concentrate of steel-containing parts and a residual fraction.