Duisburger Kupferhutte

Karl Lippert

Herbert Kudelka

Heinz Planken

A process for recovering metallic values from arsenic-containing copper cementate sludges. The cementate is admixed with lime in an amount sufficient to form calcium sulfate by reaction with any water-soluble sulfate present in the cementate, and calcium arsenate from the arsenic present in the cementate. The admixture is roasted in an oxygen-containing atmosphere at a temperature above about 300.degree. C, to oxidize the metallic values to a state in which said values are soluble in aqueous acid. The roasted material is leached with aqueous acid to dissolve said values. The values can be recovered from the solution produced in the leaching step by known procedures. By the process of the invention, polluting by arsenic is prevented.

Process for working up copper cementate sludges

A process for working up of a concentrate containing Cu, Zn, and precious metal including at least one of Ag or Au. In a first stage, the concentrate or the concentrate in modified form is leached for hydrometallurgically dissolving out the copper and zinc and leaving a residue containing the precious metal, and the leach liquor is separated from the residue. In a second stage, residue is subjected to a chlorinating sulfatizing roasting, and the roasted residue is leached with a selective solvent for the precious metal, e.g. aqueous NaCl, for dissolving the precious metal out of the residue.

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Duisburg, Germany

Karl Lippert