Beijing University of Technology

The Broken Hill Associated Smelters Proprietary Limited

Robert George Kelly

Frank Lawson

Denby Harcourt Ward

Glen Waverley

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.

Continuous sulphur drossing apparatus

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 bullion in the dross separation vessel; and continuously withdrawing decoppered bullion from the dross separation vessel.

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Port Pirie, Australia

Robert George Kelly