E-waste is an important secondary source of precious metals. Especially discarded printed circuit boards (PCBs) contain high concentrations of precious metals. In recent years, the bacterial leaching was more widely preferred due to its low environmental impact and cost in the recovery of these precious metals. In this study, a PCBs-adapted pure culture of A. ferrooxidans, A. thiooxidans and PCBs-adapted mixed culture of A. ferrooxidans and A. thiooxidans were used for recovery of the copper, zinc, nickel and aluminum. The effects of initial pH, inoculum bacteria and pulp density were investigated to determine the optimum conditions in bioleaching experiments. Optimum experimental conditions in mixed culture experiments were determined as 10% inoculum bacteria, 10% pulp density, 10 days leaching time, 1.8 initial pH, 30 ± 2 ℃ initial temperature, 125 µm particle size and 180 rpm stirring speed. As a result of triple experiments conducted under optimum conditions, metal recovery efficiencies for copper, nickel, zinc and aluminum were 94, 89, 88 and 59%, respectively. These results were demonstrated that the experiments with mixed culture were more effective in recovering precious metals such as copper, nickel, zinc and aluminum than others.

电子垃圾是贵金属的重要二次来源。特别是废弃的印刷电路板 (PCB) 含有高浓度的贵金属。近年来，由于细菌浸出对环境的影响小且回收这些贵金属的成本低，因此受到越来越广泛的青睐。在本研究中，A. ferrooxidans、A. thiooxidans和 PCBs 适应的A. ferrooxidans和A. thiooxidans混合培养物的PCBs 适应纯培养物用于回收铜、锌、镍和铝。研究了初始 pH 值、接种细菌和纸浆密度的影响，以确定生物浸出实验的最佳条件。混合培养实验中的最佳实验条件确定为10%接种菌、10%纸浆密度、10天浸出时间、1.8初始pH、30±2℃初始温度、125μm粒径和180rpm搅拌速度。作为在最佳条件下进行的三重实验的结果，铜、镍、锌和铝的金属回收率分别为 94%、89%、88% 和 59%。这些结果表明，混合培养实验比其他方法更有效地回收铜、镍、锌和铝等贵金属。