Abstract Bioleaching has been widely applied to recover metals from sulfide minerals at medium or high temperatures, however, little is known about the bioleaching at low temperature. Electrochemical analysis techniques such as cyclic voltammetry (CV), potentiodynamic polarization curve and electrochemical impedance spectroscopy (EIS), combined with surface detection methods such as scanning electron microscopy (SEM), applied to study the electrochemical behavior of chalcopyrite during bioleaching at 6 °C. Chalcopyrite bioleaching experiments demonstrated that the maximum cell density could achieve 5.3 × 108 cells/mL. Copper extraction by Acidithiobacillus ferrivorans could reach 1.92 g/L, which is better than the 0.67 g/L of sterile experiment. CV tests found that as the leaching time passed, the anodic and cathodic current signals decreased and the anodic peak moved gradually from low potential to high potential. The increase of corrosion potential and the decrease of corrosion current in potentiodynamic polarization proved the passivation on the surface of the chalcopyrite. EIS results showed that ion exchange resistance increased from 306.1 Ω to 1913.0 Ω, which is larger than the passivation film impedance originated from elemental sulfur and polysulfide on the mineral surface. It suggested that the impedance of chalcopyrite electrode at low temperature is mainly due to ion exchange impedance but not passivation layer, which is different from the bioleaching at normal or high temperature.

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嗜酸硫杆菌YL15低温生物浸出黄铜矿溶解钝化行为的电化学研究

摘要 生物浸出已广泛应用于中高温下硫化矿物中金属的回收，但对低温下生物浸出知之甚少。循环伏安法（CV）、动电位极化曲线和电化学阻抗谱（EIS）等电化学分析技术，结合扫描电子显微镜（SEM）等表面检测方法，应用于研究黄铜矿在6°C生物浸出过程中的电化学行为. 黄铜矿生物浸出实验表明，最大细胞密度可达到 5.3 × 108 个细胞/mL。铁酸硫杆菌提取铜可达1.92 g/L，优于无菌实验的0.67 g/L。CV 测试发现，随着浸出时间的推移，阳极和阴极电流信号降低，阳极峰值逐渐从低电位向高电位移动。动电位极化腐蚀电位的增加和腐蚀电流的减小证明了黄铜矿表面的钝化。EIS 结果表明，离子交换电阻从 306.1 Ω 增加到 1913.0 Ω，大于矿物表面元素硫和多硫化物产生的钝化膜阻抗。这表明低温下黄铜矿电极的阻抗主要是由于离子交换阻抗而不是钝化层，这与常温或高温下的生物浸出不同。动电位极化腐蚀电位的增加和腐蚀电流的减小证明了黄铜矿表面的钝化。EIS 结果表明，离子交换电阻从 306.1 Ω 增加到 1913.0 Ω，大于矿物表面元素硫和多硫化物产生的钝化膜阻抗。这表明低温下黄铜矿电极的阻抗主要是由于离子交换阻抗而不是钝化层，这与常温或高温下的生物浸出不同。动电位极化腐蚀电位的增加和腐蚀电流的减小证明了黄铜矿表面的钝化。EIS 结果表明，离子交换电阻从 306.1 Ω 增加到 1913.0 Ω，大于矿物表面元素硫和多硫化物产生的钝化膜阻抗。这表明低温下黄铜矿电极的阻抗主要是由于离子交换阻抗而不是钝化层，这与常温或高温下的生物浸出不同。其大于源自矿物表面元素硫和多硫化物的钝化膜阻抗。这表明低温下黄铜矿电极的阻抗主要是由于离子交换阻抗而不是钝化层，这与常温或高温下的生物浸出不同。其大于源自矿物表面元素硫和多硫化物的钝化膜阻抗。这表明低温下黄铜矿电极的阻抗主要是由于离子交换阻抗而不是钝化层，这与常温或高温下的生物浸出不同。