Abstract: In the roasting (oxidation) of mixed zinc sulphide/lead sulphide concentrates, to give an oxidic product for reduction, improved sulphur elimination and reduced lead volatilization are achieved by mixing 2-20% by weight of zinc oxide with the mixed sulphide materials, forming pellets of 2-15 mm diameter and roasting these under controlled oxidation conditions, firstly at a lower temperature and then at a higher temperature; preferably at 850.degree.-950.degree. C. for the first stage and at 950.degree.-1050.degree. C. for the last stage.

Abstract: A method of smelting an oxide charge containing lead and copper in a blast furnace, wherein molten lead bullion flowing to the furnace bottom and containing at least 8% by weight of copper is diluted with metallic lead of lower copper content in the furnace shaft, or in the hearth at the bottom of the furnace, or in a forehearth into which furnace products are passed from the furnace, or in a transfer ladle into which lead bullion passes from the forehearth.

Abstract: A tuyere for a blast furnace, the main body of the tuyere being in the form of a tube with a central bore and the nose portion of the tuyere having a downwardly-inclined hood-like extension of the upper wall of the tube, whereby gas passing through the nose of the tuyere is deflected downwardly by the said extension, which extension has a gas outlet aperture of greater area than the cross-sectional area of the bore of the tube.

Abstract: A process for leaching copper and arsenic from copper dross containing copper arsenide and separated from molten lead bullion comprises leaching the dross with an aqueous ammoniacal solution containing arsenate as the predominant anion under oxidizing conditions to obtain a leachate, removing copper from the leachate to obtain a raffinate and re-cycling raffinate to the leaching stage, and removing a bleed of raffinate from the circuit and precipitating a substantially insoluble arsenic compound from the raffinate bleed to remove arsenic from the circuit.

Abstract: A method of charging a zinc-smelting blast furnace with alternate loads of coke and zinc oxide material from a hopper by means of a central bell/annular bell charging device, in which the annular bell is lowered by a predetermined fixed distance, wherein the time ratio of the time taken to discharge the hopper contents to the time taken for the annular bell to be lowered the predetermined fixed distance is less than unity, preferably between 0.67 and a value less than 1.

Abstract: A substantially spherical pellet composed predominantly of lead sulphide which is coated with predominantly zinc sulphide material. The lead sulphide core is from 2-6 mm in diameter and the zinc sulphide coating has a thickness of from 1-3 mm. The weight ratio of zinc sulphide to lead sulphide is from 1.5:1 to 2.5:1.

Abstract: A lead-splash condenser for condensing metal vapor from a hot gas stream, comprising a plurality of condensation chambers, spray generating means provided in each condensation chamber, an inlet for passage of a hot gas containing metal vapor to the first condensation chamber, an outlet for passage of the gas from the last condensation chamber, and a stack communicating with the outlet of the last condensation chamber, wherein the stack is provided with gas deflector means for deflecting the gas stream from the side wall of the stack facing the outlet of the last condensation chamber so as to obtain a more uniform gas distribution in the stack, and to thereby reduce the rate of droplet elutriation in the gas stream leaving the condenser.

Abstract: A method of smelting an oxide charge containing lead and copper in a blast furnace, wherein molten lead bullion flowing to the furnace bottom and containing at least 8% by weight of copper is diluted with metallic lead of lower copper content in the furnace shaft, or in the hearth at the bottom of the furnace, or in a forehearth into which furnace products are passed from the furnace, or in a transfer ladle into which lead bullion passes from the forehearth.

Abstract: A method of extracting copper from an aqueous ammoniacal leach solution which is derived from the leaching of copper dross and which contains impurity cations, comprising contacting the leach solution with a copper-selective organic phase to take copper into the organic phase and then stripping the copper from the organic phase into an aqueous phase, the organic phase being washed with a dilute acid before stripping, wherein before the organic phase is washed with the dilute acid the concentration of copper in the organic phase is reduced below a level at which poor phase separation occurs under acid conditions.