Abstract Chalcopyrite leaching at moderate temperature exhibits slow kinetics due to surface passivation. The presence of iodine has been reported to significantly enhance copper dissolution from chalcopyrite in ferric sulfate media at ambient temperature. However, the key factors controlling the reaction rate and the mechanisms have not been well understood. This study quantified the effect of different parameters on the kinetics of copper extraction in the presence of iodine and elucidated the possible rate-limiting steps. A series of leaching tests was carried out in PTFE (polytetrafluoroethylene) bottles with high chemical resistance to investigate the effect of solution potential (673–769 mV vs SHE), total iodide concentration (50–200 mg/L), particle size (53–90 μm), and temperature (25–45 °C) on chalcopyrite concentrate leaching. PTFE bottles were used to prevent iodine loss via evaporation and iodine corrosion of the experimental apparatus. The experimental results show that redox potential was the principal factor determining the leaching performance via controlling the aqueous iodine speciation. In the potential range where triiodide or diiodine dominates, the copper extraction increased with increasing potential, increasing total iodide concentration, and increasing temperature. Particle size did not affect the kinetics, possibly resulting from the narrow size ranged used. A preliminary kinetic model shows that the reaction orders with respect to Fe(III)/Fe(II) concentration ratio and the total iodide concentration were 0.36 and 0.91, respectively. The activation energy (47 kJ/mol) was significantly lower than those reported for the conventional chalcopyrite leaching in ferric sulfate media, suggesting that the presence of iodine changed the reaction mechanism. Further investigation is required to uncover the exact role of different iodine species in the leaching process.

中文翻译：

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碘辅助硫酸铁介质中黄铜矿浸出动力学模拟

摘要 由于表面钝化，黄铜矿在中等温度下浸出表现出缓慢的动力学。据报道，碘的存在可显着提高环境温度下硫酸铁介质中黄铜矿中铜的溶解度。然而，控制反应速率的关键因素和机制尚未得到很好的理解。该研究量化了不同参数对碘存在下铜提取动力学的影响，并阐明了可能的限速步骤。在具有高耐化学性的 PTFE（聚四氟乙烯）瓶中进行了一系列浸出试验，以研究溶液电位（673–769 mV vs SHE）、总碘化物浓度（50–200 mg/L）、粒径（53 –90 μm) 和温度 (25–45 °C) 对黄铜矿精矿浸出的影响。聚四氟乙烯瓶用于防止实验装置因蒸发和碘腐蚀而造成的碘损失。实验结果表明，氧化还原电位是通过控制碘水形态决定浸出性能的主要因素。在三碘化物或二碘化物占主导地位的电位范围内，铜提取量随着电位的增加、总碘化物浓度的增加和温度的升高而增加。粒度不影响动力学，可能是由于所用的粒度范围窄所致。初步动力学模型显示，关于 Fe(III)/Fe(II) 浓度比和总碘化物浓度的反应顺序分别为 0.36 和 0.91。活化能 (47 kJ/mol) 显着低于硫酸铁介质中常规黄铜矿浸出所报道的活化能，表明碘的存在改变了反应机理。需要进一步调查以揭示不同碘种类在浸出过程中的确切作用。