The electrochemistry of surface oxidation of chalcopyrite

Journal Article · Sat Jun 01 04:00:00 EDT 1985 · J. Electrochem. Soc.; (United States)

DOI:https://doi.org/10.1149/1.2114117· OSTI ID:5262502

Biegler, T; Horne, M D

Linear sweep voltammetry with a freshly renewed surface of a chalcopyrite (CuFeS/sub 2/) mineral electrode shows a small anodic prewave in acid electrolytes. The main anodic reaction, with complete dissolution of copper and iron, occurs at more positive potentials. Experiments under nitrogen show that the prewave is not a consequence of atmospheric oxidation during surface preparation. The prewave represents a surface oxidation of chalcopyrite to form a thin passivating film. The charge passed in forming this film is around 2 mC cm/sup -2/ for a polishe surface. The prewave reaction is identified with the initial phase of the oxidative dissolution or leaching of chalcopyrite. Contrary to the reported behavior at 80/sup 0/C, the surface film is stable at 25/sup 0/C for long periods at open circuit Various evidence, including the relative charges passed in forming and then reducing the surface film, and the presence of dissolved copper, leads to the following suggested stoichiometry for the prewave reaction CuFeS/sub 2/ ..-->.. 0.75CuS + 0.25Cu/sup 2 +/ + Fe/sup 2 +/ + 1.25S + 2.5e. The product layer containing CuS and S is about 3 nm thick.

• Research Organization: CSIRO Division of Mineral Chemistry, Port Melbourne, Victoria
• OSTI ID: 5262502
• Journal Information: J. Electrochem. Soc.; (United States), Journal Name: J. Electrochem. Soc.; (United States) Vol. 132:6; ISSN JESOA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400400* -- Electrochemistry
CHALCOGENIDES
CHALCOPYRITE
CHEMICAL REACTIONS
CHEMISTRY
COPPER
COPPER COMPOUNDS
COPPER SULFIDES
DISSOLUTION
ELECTROCHEMISTRY
ELECTRODES
ELECTROLYTES
ELEMENTS
IRON COMPOUNDS
IRON SULFIDES
METALS
MINERALS
OXIDATION
PASSIVATION
SULFIDE MINERALS
SULFIDES
SULFUR COMPOUNDS
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
VOLTAMETRY