Process for the separation of copper sulfide from metallic lead

Abstract

Copper sulfide in the presence or absence of metallic copper contained in a dross obtained from the copper drossing of lead bullion is separated from metallic lead entrained or occluded in the dross by introducing the dross into a vessel other than a reverberatory furnace, usually a kettle, also introducing an alkali metal sulfide, preferably sodium sulfide, into the kettle, and heating the dross and alkali metal sulfide together in the kettle at an elevated temperature not in excess of 1200.degree. F. and for a time sufficient to melt together the dross and alkali metal sulfide. The thus-obtained molten dross releases the entrained molten lead which falls to the bottom of the kettle. The molten dross and molten alkali metal sulfide form a low melting copper sulfide-alkali metal sulfide matte on the surface of the resulting pool of the released molten lead, and the matte is separated from the molten lead pool, for instance by being lifted off the pool by means of a hook positioned in the matte layer while molten and retained in the matte layer while the matte layer is permitted to solidify on the molten lead pool surface. Copper sulfide in the presence of metallic copper can also be separated from metallic lead and tin contained in solder drosses, e.g. high tin-bearing solder drosses, or in other drosses in accordance with this invention.