Abstract: A municipal or like refuse, from which large articles of metals have been removed, is mixed with an alkaline substance like limestone preferably in a triple screw mixer, and then advanced along the pyrolysis path in which the refuse mixture is subjected to heat from combustion gases from an incineration chamber therebelow. A portion of the pyrolyzed product is recycled to the upstream side of that path and the remainder of the pyrolyzed product is scrubbed with an aqueous medium, e.g. water and/or aqueous acetic acid and the washed pyrolyzed product is then incinerated to produce the combustion gas.