Abstract: A treating method of recovering zinc in the metal state from a waste containing the zinc in the oxide state, lead, chlorine, fluorine, and water comprising a mixing process 90 of obtaining a to-be-treated mixed material 70 by mixing a steel dust 7 and a reducing material 8 together; a chlorine recovery process 91 of recovering the chlorine and the water by heating the to-be-treated mixed material 70; a lead recovery process 92 of recovering fluorine and lead by heating the to-be-treated mixed material 70 under vacuum; a zinc recovery process 93 of recovering metallic zinc by heating the to-be-treated mixed material 70 at a temperature higher than that in the lead recovery process 92 with the vacuum state maintained so as to reduce and vaporize zinc; and a residue recovery process 94 of recovering a residue 79 of the to-be-treated mixed material 70. This construction allows the metallic zinc to be recovered at a high purity from a zinc oxide-containing waste and an on-site treatment to be accomplished.

Abstract: A method of treating dust exhausted from a melting furnace in melting an iron-contained material, comprising the steps of: melting the iron-contained material, with air inside the melting furnace shut out from outside air and collecting the dust from the melting furnace into which a gas exhausted from the melting furnace and containing the dust is introduced; performing a lead-collecting process of collecting water, chloride, fluorine, and lead by heating the exhausted dust in vacuum; and performing a zinc-collecting process of collecting metallic zinc contained in the dust by heating a residue of the exhausted dust in vacuum.

Abstract: Dusts containing zinc and/or lead in the form of oxides and one or more reducing agents are mixed with each other before or after being introduced into a heat treatment furnace. The mixture is heated to a given temperature range under a substantial vacuum so that the zinc and/or lead in the form of oxides are reduced to zinc and/or lead in the state of pure metals and evaporated in the furnace. The evaporated zinc and/or lead are introduced into a retrieving container also under a substantial vacuum and at a given temperature where the evaporated zinc and/or lead pure metals are condensed and retrieved.