Boliden Aktiebolag

Kenneth A Sjoberg

Lars A Hedstrom

Nils F Lindstrom

The invention relates to an electrowinning cell for extracting metals in powder form from solutions, and simultaneously oxidizing the solution. The cell is characterized by radially extending electrodes comprising mutually alternating anodes and cathodes; by a diaphragm which delimits separate anode and cathode chambers, of which the cathode chamber forms an outer space; and a stirring means arranged in the anode chamber and operative to ensure a large flow of electrolyte across the anode surfaces. The base of the cathode chamber is preferably conical in shape.

Electrowinning system

The invention relates to a method for selectively recovering lead from complex sulphidic non-ferrous metal concentrates in an electrolytic cell incorporating at least one anode and one cathode and an electrolyte containing chlorine ions, at a temperature beneath the boiling point of the concentrate-containing electrolyte and at a pH beneath 7. Sulphur present in the concentrate is converted substantially into elementary form, and at least the major part of the lead content passes into solution and is then precipitated selectively by cathodic processes. The invention is characterized in that the concentrate is slurried in an electrolyte having a chloride-ion strength above about 2 M, preferably in the range 3-5 M, to form a suspension which is caused to flow into contact with or adjacent the surface of anodes located in the cell; and in that the highest possible anodic current density considering required selectivity is maintained during the electro-winning process.

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Boliden, Sweden

Kenneth A Sjoberg