In a method for processing used cathode material containing carbon, in particular used cathode troughs from aluminum production, the cathode material is put into a shaft furnace and, in order to gasify carbon, is subjected to a thermal treatment in the shaft furnace at a temperature above the ignition temperature of the carbon and above the evaporation temperature of toxic substances contained in the used cathode material. The reaction gases are conducted co-current with the carbon in a first longitudinal section of the shaft furnace and countercurrent to the carbon in a second longitudinal section of the shaft furnace. The reaction gases are drawn from a region of the shaft furnace having an enlarged cross-section between the longitudinal sections and are preferably subjected to an after-treatment.