The Broken Hill Associated Smelters Proprietary Limited

James Dixon Iley

Denby Harcourt Ward

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. C higher than the average temperature in the lower separation zone, separating crust particles from the bullion in the lower separation zone, causing the crust particles to move upwardly in the vessel and the bullion to move downwardly in the vessel, separating entrained lead from the crust particles in the upper liquation zone so as to form enriched crusts, removing the enriched crusts continuously or intermittently from the upper surface of the material in the vessel, and withdrawing debismuthised product lead continuously from at or near the lower end of the lower separation zone.

Process for debismuthizing lead

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crusts being removed from the upper surface of the material in the vessel, and the debismuthised product lead being withdrawn from near the lower end of the lower separation zone. The input lead and the reagent may be mixed in a mixing chamber in the separation vessel or in one or more separate mixing pots.

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Port Pirie, Australia

James Dixon Iley