Process for utilizing slag (2, 2") which originates from the iron smelting industry and is obtained in steel works convertors and contains oxidic iron particles, with addition of a reducing agent and reduction of oxidic iron particles of the slag (2, 2") and also any other metal oxides present by means of this reducing agent , characterized by the combination of the following features: - charging of the slag (2, 2") into a reactor vessel , preferably into a tiltable laden reactor , onto a residual iron melt which contains dissolved carbon, slowly and continuously over a prolonged period of time, - electric heating of the slag and of the residual iron melt and also freshly formed iron melt over a prolonged period of time, - blowing-in of a carbon-containing reducing agent by means of gas, preferably inert gas, over a prolonged period of time by means of a lance into a region close to the interface between slag and iron melt or directly into the iron melt , with dissolution of carbon in the iron melt and with mixing of iron melt and slag , - dissolution of the carbon of the reducing agent in the iron melt and - reduction of oxidic iron particles of the slag to form metallic iron and CO over a prolonged period of time, - formation of a foamed slag by means of the CO formed over a prolonged period of time, - introduction of an oxygen-containing gas or of oxygen into the foamed slag and after-combustion of CO to CO 2 over a prolonged period of time, with the introduction being carried out in the upper half, preferably in the upper third, of the height of the slag , - flushing of the bottom of the reactor vessel with inert gas over a prolonged period of time, - discharge of the treated slag and optionally - subsequently discharge of iron melt leaving a residual iron melt containing dissolved carbon in the reactor vessel , with the term prolonged period of time referring to the period of time essentially from discharge of slag and optionally iron melt until the subsequent discharge of slag. - charging of the slag (2, 2") into a reactor vessel , preferably into a tiltable laden reactor , onto a residual iron melt which contains dissolved carbon, slowly and continuously over a prolonged period of time, - electric heating of the slag and of the residual iron melt and also freshly formed iron melt over a prolonged period of time, - blowing-in of a carbon-containing reducing agent by means of gas, preferably inert gas, over a prolonged period of time by means of a lance into a region close to the interface between slag and iron melt or directly into the iron melt , with dissolution of carbon in the iron melt and with mixing of iron melt and slag , - dissolution of the carbon of the reducing agent in the iron melt and - reduction of oxidic iron particles of the slag to form metallic iron and CO over a prolonged period of time, - formation of a foamed slag by means of the CO formed over a prolonged period of time, - introduction of an oxygen-containing gas or of oxygen into the foamed slag and after-combustion of CO to CO 2 over a prolonged period of time, with the introduction being carried out in the upper half, preferably in the upper third, of the height of the slag , - flushing of the bottom of the reactor vessel with inert gas over a prolonged period of time, - discharge of the treated slag and optionally - subsequently discharge of iron melt leaving a residual iron melt containing dissolved carbon in the reactor vessel , <EOS>