Asarco LLC

William Lafayette Scott

Leo J Bulvanoski

Carl R Di Martini

Carl Richard DiMartini

Herbert E Howe

Lead is separated from material containing lead sulfide, e.g., galena ore concentrate, by a substantially autogenous process involving establishing a pool of molten lead in a kettle, adding a metallic alkali metal, e.g., metallic sodium, to the molten lead in an amount sufficient to reduce the combined lead of the lead sulfide to metallic lead, adding the ore concentrate to the molten lead pool, and mixing together the metallic sodium, molten lead and ore concentrate. The sodium reacts rapidly and exothermically with the lead sulfide to reduce the combined lead of the lead sulfide to metallic lead and form sodium sulfide. The thus-liberated metallic lead reports in the molten lead pool, and a matte phase containing the sodium sulfide separates from the molten lead and forms on the surface of the molten lead pool. Lead sulfide from an excess of the ore concentrate, or other suitable added flux, which is usually added to the molten lead pool, serves to flux the sodium sulfide-containing matte phase to attain desired fluid and low melting characteristics of the matte phase. The process herein employs a kettle as the reactor, ordinarily the steel refining kettle of a lead refinery, is a low temperature process requiring temperatures above the melting point of lead but ordinarily not above 650.degree. C., and does not discharge polluting SO.sub.2 into the atmosphere.

Low temperature, non-SO.sub.2 polluting, kettle process for separation

Lead is separated from material containing lead sulfide, e.g. galena ore concentrate, by a substantially autogenous process involving establishing a pool of molten lead in a kettle, adding a metallic alkali metal, e.g. metallic sodium, to the molten lead in an amount sufficient to reduce the combined lead of the lead sulfide to metallic lead, adding the ore concentrate to the molten lead pool, and mixing together the metallic sodium, molten lead and ore concentrate. The sodium reacts rapidly and exothermically with the lead sulfide to reduce the combined lead of the lead sulfide to metallic lead and form sodium sulfide. The thus-liberated metallic lead reports in the molten lead pool, and a matte phase containing the sodium sulfide separates from the molten lead and forms on the surface of the molten lead pool. Lead sulfide from an excess of the ore concentrate, or other suitable added flux, which is usually added to the molten lead pool, serves to flux the sodium sulfide-containing matte phase to attain desired fluid and low melting characteristics of the matte phase. The process herein employs a kettle as the reactor, ordinarily the steel refining kettle of a lead refinery, is a low temperature process requiring temperatures above the melting point of lead but ordinarily not above 650.degree. C., and does not discharge polluting SO.sub.2 into the atmosphere.

Antimony values are separated from a material containing a sulfo-antimony compound of copper, e.g. tetrahedrite ore concentrate, by a process involving establishing a pool of molten lead, adding a metallic alkali metal, e.g. metallic sodium, to the molten lead in an amount which is sufficient to reduce the combined antimony of the sulfo-antimony compound or compounds of copper of the tetrahedrite to metallic antimony, adding the tetrahedrite ore concentrate to the molten lead, and mixing together the alkali metal, molten lead, and tetrahedrite ore concentrate. The alkali metal and sulfo-antimony compound of copper are reacted together in the presence of the molten lead for a period which is sufficient to reduce the antimony of the sulfo-antimony compound of copper to metallic antimony and to form one or more sulfo-alkali metal compounds of copper, and a matte phase which separates from the molten lead. The reduced, metallic antimony passes into the molten lead pool, and the sulfo-alkali metal compound or compounds of copper report in the matte phase on the surface of the molten lead pool. The matte phase is separated from the molten lead. The metallic antimony is then recovered from the lead. Alternatively, if lead- and antimony-containing alloy is desired as a product, the antimony is retained in the lead, and additional antimony and/or lead may or may not be incorporated into the alloy, as desired or required, to obtain the desired alloy composition. Should the alloy product be a desired product, the starting lead of the molten pool will ordinarily not be a liquated, rough drossed lead bullion, but instead another lead such as, for example pure lead or antimonial lead. The process herein is a relatively low temperature process employing temperatures of the molten lead pool above the melting point of lead but ordinarily not in excess of 650.degree. C. Further, the instant process does not require a smelting furnace but is ordinarily carried out in a kettle.

Low temperature, non-SO.sub.2 polluting, kettle process for the

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.

Method for the concentration of alkaline bismuthide in a material also

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.2, by electrolysis, or by blowing the molten Pb-Bi alloy with air in a cupel to form litharge which is skimmed off.

Process for the recovery of bismuth

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.

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Lebanon, NJ, United States of America

William Lafayette Scott