Abstract: Waste material is disposed of and its usable constituents recovered by feeding the waste material downwardly through a vertical shaft in which its temperature is progressively raised thereby driving off volatile matter and thermally degrading appropriate portions of the material to provide a gaseous discharge suitable for use as a fuel. Material such as metal and other non-volatilizable substances eventually reach a furnace chamber which has a temperature of at least 1600.degree. C where they are liquified and tapped from the chamber. The heavier metal component is tapped from a point lower than the point at which other liquid residues are tapped to enable the metal to be recycled.