Electrochemical dissolution of copper sulfides using a fluidized bed electrochemical reactor

Technical Report · Sat Dec 01 04:00:00 EST 1984

OSTI ID:6054405

Felker, D L

A 2-stage process for the separation and recovery of the Cu, Fe and S from chalcopyrite (CuFeS/sub 2/) was investigated. The overall process dissolves and separates the Cu and Fe in CuFeS/sub 2/ into a Fe rich electrolyte and a Cu rich electrolyte. The S in CuFeS/sub 2/ reacts to form H/sub 2/S and S/sup 0/. A model was developed to explain the results of the chalcopyrite reduction experiments, based on the assumptions that the rate of chalcopyrite reduction is controlled by the H/sup +/ content at the reacting surface/electrolyte interface and the H/sup +/ content at the interface is controlled by the diffusion of H/sup +/ through the porous chalcopyrite reduction product layer. The model is in general agreement with the experimental results. Production of Cu (I) during the dissolution of the chalcopyrite reduction product layer occured only when using a 4 M HCl anolyte. The amount of Cu (I) produced fell sharply when the total cell current exceeded 19.5 A. Complete oxidation of the copper sulfide layer was easily accomplished. Oxidation of the chalcopyrite reduction product layer was possible in 4 M HC1O/sub 4/, 2 M H/sub 2/SO/sub 4/ and 2.7 M H/sub 3/PO/sub 4/, except that Cu (II) was the only dissolution product and dissolution of the copper sulfide was replaced by O/sub 2/ evolution when the solid phase stoichiometry reached CuS. Addition of Cl/sup -/ to the electrolyte prevented the production of O/sub 2/ and caused the CuS to react, forming Cu (II) and S/sup 0/. The presence of Cl/sup -/ also caused the evolution of Cl/sub 2/. The chalcopyrite reduction product layer produced in 4 M HCl was identified as Cu/sub 1.8/S. The rate of chalcopyrite reduction was severely limited by the thickness of the Cu/sub 1.8/S product layer. Removal of the chalcopyrite reduction product layer using

• Research Organization: Ames Lab., IA (USA)
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 6054405
• Report Number(s): IS-T-1117; ON: DE85005117
• Country of Publication: United States
• Language: English

Related Subjects

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