Abstract: Bismuth is recovered as elemental bismuth or as a Pb-Bi alloy from an air-pervious residue cake of de-bismuthizing dross of concentrated alkaline bismuthide content, by heating the cake in air to the ignition temperature of the cake to ignite the cake, and burning autogenously in a flameless or substantially flameless combustion the thus-ignited cake to oxidize the alkali and a portion of the lead to the exclusion of the bismuth. A powder-like residue, formed by the burning, comprises bismuth, lead, lead oxide and alkali oxide. The lead oxide and alkali oxide of the residue are then selectively dissolved in an oxide-dissolving flux, e.g. molten lead chloride, and the flux containing the lead oxide and alkali oxide is skimmed from the resulting lead bismuthide alloy. The lead of the alloy can, if desired, be separated to recover elemental bismuth, for example, by reacting the Pb-Bi alloy in molten droplet or molten particulate form with Cl.sub.2 to form PbCl.sub.

Abstract: Alkaline bismuthide is concentrated in a debismuthizing dross comprising the alkaline bismuthide and molten lead by a method involving charging the dross onto a heat-resistant screen or sieve of suitable mechanical strength. The screen has openings of such size as to enable the formation and retention thereon of a molten lead-pervious residue cake comprising particles of the alkaline bismuthide, for example of crystals of calcium magnesium bismuthide (Ca Mg.sub.2 Bi.sub.2). The dross is subjected on the screen to the influence of a partial vacuum drawn from the opposite side of the screen from the dross, and the molten lead is sucked or pulled through pore channels of the porous residue cake of the alkaline bismuthide particles which is formed on the screen, and without any significant physical compression of the cake with attendant blockage of the pores of the cake, and then through the screen openings under the influence of the partial vacuum.

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.