Abstract: Apparatus for the continuous sulphur drossing of lead to reduce its copper content including a plurality of reaction vessels arranged in series, each reaction vessel having a curved bottom and a stirrer for creating a vortex of the contents. Bullion and sulphur are fed into the series through a vortex at controlled rates and through the series at controlled temperatures and a controlled total reaction time, optimally between 8 and 15 minutes. The bullion, dross and unreacted sulphur, if any, are overflowed from vessel to vessel and into an unagitated vessel for separation of the dross and bullion. The bullion feed device splits the undrossed bullion into a metered stream and an unmetered stream, the unmetered stream being utilized to carry away the separated dross for further processing.

Abstract: A continuous process for debismuthising lead containing one or more alkaline earth metals or alloys thereof, comprising continuously adding thereto a reagent selected from the group consisting of antimony, arsenic and alloys containing antimony and/or arsenic, so as to form a crust/bullion mixture, continuously introducing the crust/bullion mixture into the lower separation zone of a separation vessel having an upper liquation zone and a lower separation zone, maintaining the temperature in the upper liquation zone between 330.degree. and 480.degree. C and maintaining the temperature in the lower separation zone between the freezing point of lead and 350.degree. C, the average temperature in the upper liquation zone being at least 15.degree.

Abstract: A continuous sulphur drossing process for the decoppering of lead comprising the steps of flowing lead bullion into the first of a series of at least two reaction vessels; continuously agitating the lead bullion in the first reaction vessel, adding sulphur to the lead bullion during the continuing agitation; continuously and concurrently transferring the lead bullion, dross arising from the copper reacted with the sulphur, and any unreacted sulphur from each reaction vessel to the next in the series without backmixing; agitating the contents of each reaction vessel; maintaining the total residence time of the materials in the reaction vessels below that in which a significatn amount of reversion to elemental copper would occur, thereby substantially preventing re-solution of copper in he bullion; continuously and concurrently transferring decoppered bullion and dross from the final reaction vessel in the series to an unagitated dross separation vessel; removing the dross from the surface of the decoppered bul

Abstract: Apparatus for debismuthising lead containing one or more alkaline earth metals or alloys thereof, including a separation vessel having independently temperature-controlled upper liquation and lower separation zones, devices for adding a reagent selected from the group consisting of antimony, arsenic and alloys containing antimony and/or arsenic to the input lead to form a crust/bullion mixture and continuously and directly introducing the crust/bullion mixture into the lower separation zone of the vessel at a point below the upper liquation zone, the crust particles being separated from the bullion in the lower separation zone and moving upwardly in the vessel, the entrained lead being separated from the crust particles in the upper liquation zone and moving downwardly in the vessel, the enriched crusts being removed from the upper surface of the material in the vessel, and the debismuthised product lead being withdrawn from near the lower end of the lower separation zone.