氧化亚铁硫杆菌浸出废弃挠性PCB中金属的影响因素分析

废弃挠性PCB是资源化价值高的电子废弃物之一，正需环境友好的方法回收其所含的多种有价金属。采用显微镜对破碎后的挠性PCB粉样进行解离情况观察，发现破碎法难以将挠性PCB中的金属与非金属解离。通过设计单因素实验，研究挠性PCB粉末粒度大小、添加量、培养液初始pH、菌接种量、活化时间以及FeSO4·7H2O添加量6个因素对氧化亚铁硫杆菌（Acidithiobacillus ferrooxidans，简称A.f菌）浸出挠性PCB中金属过程的影响。结果表明，A.f菌不能浸出挠性PCB中Au，但Cu、Ni可以有效浸出且最优化条件为：10 g·L-1挠性PCB、粒度0.25~0.42 mm、培养基初始pH 2.5、菌接种量5%、菌活化时间5 d、FeSO4·7H2O添加量30 g·L-1，金属Cu的浸出率达到90.1%，比未接种处理高出42.4%；金属Ni的浸出率达到了85.9%，比未接种处理高出了32.9%。因此，采用生物法可环境友好地回收挠性PCB中Cu、Ni，有利于废弃挠性PCB的资源化处理。

Analysis of impact factors about bioleaching metals from scrap flexible PCB by Acidithiobacillus ferrooxidans

The scrap flexible printed circuit board (PCB) is a highly valued type of electronic waste, as it contains various valuable metals suitable for recycling with environment-friendly methods. After the dissociation of crushed flexible PCB powder was observed under a microscope, the conclusion was that physical crushing could not dissociate the metals and non-metals. A subsequent experiment was aimed at optimizing the conditions that influence the A. ferrooxidans bioleaching of metals from the flexible PCB, including the particle size of the flexible PCB powder, quantity of flexible PCB powder, initial pH of the culture medium, bacteria inoculation, bacteria activation time, and the quantity of FeSO4·7H2O. The experiment results indicated that Au could not be leached by A. ferrooxidans, whereas Cu and Ni could be leached. The relevant optimizing conditions were flexible PCB 10 g·L-1, particle size of the flexible PCB 0.25 to 0.42 mm, culture medium initial pH 2.5, bacteria inoculation 5%, bacteria activation time 5 d, quantity of FeSO4·7H2O 30 g·L-1. The leaching rate of Cu was 90.1%, which was 42.4% higher than was that of the blank group. The leaching rate of Ni was 85.9%, which was 32.9% higher than was that of the blank group. Therefore, the environment-friendly bioleaching method was able to recover Cu and Ni from the flexible PCB, which is conducive to recycling the scrap flexible PCB.