A method and a device for reducing iron-oxide-containing feedstocks, in which a reducing gas is fed to a reducing unit (1) containing the iron-oxide-containing feedstocks. The reducing gas is generated by introducing a process gas having reduction potential into a heating appliance (3) for heating the process gas, which is withdrawn as reducing gas therefrom. In the heating appliance (3), heat energy is transferred to the process gas. The heat energy is formed by combustion of a fuel gas containing organic substances, including coke oven gas with addition of technically pure oxygen. The flames of the combustion have an adiabatic flame temperature of above 1000° C., wherein, in the combustion of the fuel gas, at least some of the organic substances present in the fuel gas are cracked.