International Geological Journal - Official Journal of the Carpathian-Balkan Geological Association

EVALUATION OF IDENTIFICATION METHODS FOR CHRYSOCOLLA — A Cu-SMECTITE-LIKE HYDROUS SILICATE: IMPLICATIONS FOR HEAP-LEACHING EXTRACTION OF COPPER

Pages: 111 - 121

Authors: URSULA KELM, VILMA SANHUEZA, JANA MADEJOVA, VLADIMIR SUCHA, FRANCOISE ELSASS

Abstract: Chrysocolla has been characterized by XRD, FTIR, DTA-TG, TEM and EPMA in order to clarify properties of this phase and to identify a suitable routine identification method. Chrysocolla is X-ray amorphous, although in some cases slightly sensitive to EG-treatment. IR spectra indicate a trioctahedral layer-silicate structure, resembling in many features that of trioctahedral smectites. HRTEM images do not show a phyllosilicate-like repetitive layering in accordance with XRD results. The SiO2/CuO ratio is considered responsible for the degree of crystal ordering achieved. SiO2/CuO ratio near 1 results in an amorphous phase, while SiO2/CuO near 1.3 generates more smectite-like characteristics. For routine analyses in mining operations, DTA-TG is considered feasible, once basic mineralization types are known at a site.

Keywords: Cu-leaching, mineral analysis, Cu-smectite, chrysocolla

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