Abstract A two-stage chemical-biological oxidation approach, which applied a high temperature chemical oxidation stage prior to the bio-oxidation stage, was employed to accelerate the bio-oxidation rate of Axi gold concentrate with pyrite as the main sulfide phase. The extraction levels of Fe and S were 67.0% and 72.9% in the traditional one-stage bio-oxidation approach, while the values were elevated respectively to 78.0% and 79.6% with the two-stage approach. Accordingly, the extraction rate of gold was increased from 83.6% to 90.3% when subjected to the two-stage approach. The intensification mechanism of the two-stage approach was carried out by using Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy (SEM- EDX), X-ray photoelectron spectroscopy (XPS) and particle size analysis. The results indicated that pyrite on the surface of the concentrate was partly oxidized and particle size of the concentrate diminished after the first stage (chemical oxidation), which would facilitate the subsequent bio-oxidation process.

中文翻译：

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两阶段化学-生物法生物氧化高硫难熔金精矿

摘要 采用两阶段化学-生物氧化法，在生物氧化阶段之前应用高温化学氧化阶段，以加快以黄铁矿为主要硫化物相的Axi金精矿的生物氧化速率。在传统的一级生物氧化方法中，Fe和S的提取水平分别为67.0%和72.9%，而在二级方法中分别提高到78.0%和79.6%。因此，采用两步法时，金的提取率从 83.6% 提高到 90.3%。通过使用扫描电子显微镜-能量色散X射线光谱法(SEM-EDX)、X射线光电子能谱法(XPS)和粒度分析来实施两阶段方法的强化机制。