Abstract: A method and apparatus for vitrifying waste materials containing a high quantity of carbon are provided which include the use of a secondary combustion chamber for burning the waste gases resulting from an electrically heated glass melting furnace. Additional energy is generated by this afterburning which is used to preheat batch materials used in the glass melting furnace. The particulate matter in the burned waste gases is collected in a gas washer as sludge, is thickened, and is fed back to the glass melting furnace.