嗜酸氧化亚铁硫杆菌对龙门挂架表面铜的浸出效果

龙门挂架(下称挂架)是线路板生产过程必用的固定支架,生产线路板时挂架表面会附着大量铜,使得挂架需经酸法处理后才能回用,造成大量废液和恶劣的工作环境. 为此,采用环境友好的微生物技术回收挂架表面的Cu,分析了A.f菌(Acidithiobacillus ferrooxidans,嗜酸氧化亚铁硫杆菌)脱除挂架表面Cu的效果及9K培养基不同配比(以w计,分别为100%、50%、25%)的影响,并初步解析其浸出过程. 结果表明:①添加100%的9K培养基时,A.f菌浸出挂架及其配件的溶液中ρ(Cu2+)均最高,分别达2.31和1.06 g/L,挂架及其配件表面Cu均已脱除. ②结合浸出液中ρ(Cu2+)、ρ(Fe2+)和pH随时间的变化及三者之间的相互影响关系可知,浸铜过程为A.f菌先将溶液中的Fe2+氧化为Fe3+,Fe3+再将挂架表面的Cu氧化为Cu2+. ③利用一级动力学和二级动力学模型,对3种配比培养基下配件浸出液中的ρ(Cu2+)进行曲线拟合,二级动力学模型的R2(相关系数)分别为0.888 4、0.900 8、0.844 4,均高于一级动力学的R2,表明二级动力学模型更适用于Cu的浸取行为. 该生物浸出方法有望在线路板行业中进行应用. 

Bioleaching Copper from a Gantry by Acidithiobacillus ferrooxidans

Abstract: A gantry is used to fix printed circuit board (PCB) during processing, during which copper is plated on the surface of the gantry. The gantry can be reused after its surface is treated by acid solution, but this generates a large amount of waste solution and poor working conditions. In this study, an environmentally-friendly method based on a microbial technique was used to recycle Cu. A strain of Acidithiobacillus ferrooxidans was used in the experiment. The effects of bioleaching Cu from the gantry and its accessories and the composition ratio of 9K media (100% 9K medium, 50% 9K medium, 25% 9K medium) were systematically studied, and the leaching process was preliminarily analyzed. The results showed that when adding the 100% 9K medium, the concentrations of Cu²⁺ in the leaching solutions of the gantry and its accessories were the highest:2.31 and 1.06 g/L, respectively. Cu was removed totally from the surface of the gantry. When A. ferrooxidans leached copper from the gantry, the results showed that Fe²⁺ was oxidized to Fe³⁺ in the leaching solution, and the copper might be oxidized to Cu²⁺ with the action of Fe³⁺. Further nonline fit analysis proved that the pseudo-second order kinetic model was suitable for describing the relationship between the behavior of copper dissolved and bioleaching time. In summary, the bioleaching method is expected to be applied in the PCB industry.