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Updated: May 31, 2025

Preparation of Authigenic Pyrite from Methane-bearing Sediments for In Situ Sulfur Isotope Analysis Using SIMS
Published on: August 31, 2017
Electrochemical insights into the direct dissolution of impure sphalerites and their partial oxidation in an acidic
Gholamreza Khodadadmahmoudi1,2, Saeid Karimi3, Hadi Abdollahi2
1Department of Mining and Explosives Engineering, Missouri University of Science and Technology, Rolla, MO, 65409, USA.
Abstract:
This study examined the electrodissolution mechanism of five impure sphalerite samples, which differ significantly in purity levels, along with their partially oxidized counterparts in a 0.5 M H2SO4. Partially oxidized samples were prepared through an incomplete leaching of sphalerite using H2SO4 with Fe2(SO4)3.H2O as an oxidizing agent. The original sphalerite samples and the partially oxidized samples were referred to as SP and POS samples, respectively. Analyses using XRD, SEM, Raman spectroscopy, and electrochemical techniques suggested presence of elemental sulfur and a metal-deficient layer on the surface of the POS samples. Cyclic voltammetry revealed that the sample with the highest iron content exhibited the highest electrochemical response, while the sphalerite with the highest lead concentration had the lowest activity. Electrochemical impedance spectroscopy (EIS) studies showed that impedance values were higher in the POS samples compared to the PS samples, indicating a correlation within the passivation phenomenon. In conclusion, these findings suggested that the sphalerite dissolution process is primarily controlled by charge transfer and kinetic polarization. This understanding can lead to the development of more selective and sustainable extraction methods and improving the overall economic viability of zinc hydrometallurgical operations.
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