Rendering solid residues from refuse burning, flue gas purificn. etc., inert - by fusing under reducing conditions to give harmless siliceous residue, heavy metal sump prod. and condensable volatile metal effluent gas

摘要

Process for treating solid residues which contain environmentally harmful metal oxides, obtd. e.g. from burning of refuse or from purification of flue gases, to render them inert, comprises fusing the residues under reducing conditions to yield glassy, glassy-crystalline or crystalline prods. USE/ADVANTAGE - When the solid residues are fused under reducing conditons eg in an arc furnace a molten silicate phase is formed and the environmentally harmful metal oxides such as Fe, Ni, Cr and Cu are reduced to the elementary metals which, being heavier than the silicate phase, sink to the bottom of the furnace below the silicate phase. The low boiling metals such as Zn, Cd and Hg vapourise out of the silicate phase. The vapourised elementary metals and their cpds. can be condensed and further processed. The heavy fraction in the sump of the furnace can also be collected and further processed. Harmful organic materials such as dioxin and furnace are thermally decomposed. The residual material is environmentally harmless and contains only traces of harmful metals, which cannot be leached out.