Abstract

Process for vitrifying environmentally hazardous waste material in a glass melting furnace includes forming a batch including the waste material and no more than 30 weight percent additives including phonolite and SiO2 containing substances. A gall layer 2-5 cm thick including alkali salts or alkaline earth salts is produced on the molten glass, and batch is added so that a batch layer over 5 cm thick is formed on top of the gall layer. After the batch layer is formed, the molten glass is heated solely by electrodes, and the thickness of the batch layer is maintained to produce a steep enough temperature gradient therein so that the furnace atmosphere remains relatively cool, and substantially all of the condensable components which emerge from the molten glass condense in the batch layer.