Understanding the oxidative mechanisms of chalcopyrite in various hydrothermal fluids is of great significance to improve copper extraction and to model the geochemical cycling of copper, iron, and sulfur. This paper investigated the effect of NaCl on the electrochemical oxidation of chalcopyrite at 340 °C and 21 MPa using polarization curves, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and Raman spectroscopy. The experimental results showed that NaCl can promote chalcopyrite leaching. As NaCl concentration increases, the protective property of the oxidation layer degraded. In the absence of NaCl, the oxidation layer that consisted of CuS_n, (n ≥ 1), probably with some Fe₂O₃ and Fe(OH)₃ and also in the presence of NaCl, Fe₂O₃, is the principal oxidation product. More rapid ionic diffusion and further chemical reaction contributed to the improvement of chalcopyrite dissolution with increasing NaCl concentration. A dissolution mechanism is proposed in this paper to explain the chalcopyrite leaching processes which is dependent on NaCl concentration.

中文翻译：

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氯离子对340°C和21 MPa下黄铜矿电化学氧化的影响

理解黄铜矿在各种热液中的氧化机理对于改善铜的提取以及对铜，铁和硫的地球化学循环进行建模具有重要意义。本文利用极化曲线，电化学阻抗谱（EIS），扫描电子显微镜（SEM），能量色散X射线光谱（EDS）和拉曼光谱研究了NaCl在340°C和21 MPa下对黄铜矿电化学氧化的影响光谱学。实验结果表明，氯化钠可以促进黄铜矿浸出。随着NaCl浓度的增加，氧化层的保护性能下降。在无NaCl存在下，在氧化层的组成的CuS的_Ñ，（Ñ ≥1），可能与一些的Fe ₂ ö₃和Fe（OH）₃以及在NaCl存在下，Fe ₂ O ₃是主要的氧化产物。随着NaCl浓度的增加，更快的离子扩散和进一步的化学反应有助于改善黄铜矿的溶解性。本文提出了一种溶解机理来解释依赖于NaCl浓度的黄铜矿浸出过程。