嗜酸氧化亚铁硫杆菌脱除废手机PCB表面元器件的方法研究

通过微生物法实现废手机PCB基板与其表面元器件分离，并探究最佳的工艺条件.采用嗜酸氧化亚铁硫杆菌（Acidithiobacillus ferrooxidans，以下简称A.f菌）脱除废手机PCB表面元器件，研究结果表明，经接种处理，浸出3d后，PCB表面元器件有少量脱除；浸出5d后，PCB表面元器件大部分可被脱除，仍有个体较大的元器件未被脱除；浸出7d后，PCB表面元器件被完全脱除；未接种对照组中PCB表面元器件未发生脱除.通过ICP-OES测得A.f菌作用7d的浸出液中含有大量的金属离子，而这些金属离子是构成元器件与PCB衔接处焊脚的主要组成成分，其中Ni、Zn、Al通过A.f菌作用后以离子形态进入浸出液中，焊脚中的单质Sn通过A.f菌作用后转化为离子态进入浸出液中，在浸出液中又迅速形成含锡沉淀物，在浸出第1d浸出液中Sn离子含量急速下降.通过设置不同浸出条件的单因素实验，结果表明：当培养基初始pH值为1.0，固液比为3：50，接种量为15%，温度为30℃，转速为125r/min时，A.f菌脱除手机PCB表面元器件效果最佳.浸出7d后，PCB表面元器件可被完全脱除.

Method research of acidithiobacillus ferrooxidans on removing surface components of waste mobile phone circuit board

The printed circuit board (PCB) substrate and surface components of waste mobile phone were separated using biological method in this work. Then the optimum process conditions were explored. Acidithiobacillus ferrooxidans (A.f), was used to remove surface components of PCB. Results showed that a small number of PCB surface components were removed after 3days of bioleaching. After 5days of bioleaching, most of the surface components of PCB could be removed, but still some larger individual components were not removed. After 7days of bioleaching, the surface components of PCB were removed completely. Meanwhile, there were no any components removed from the surface of PCB in the non-innoculation treatment. The results of ICP-OES showed that high concentration of metals ions, which were contained in welding foot of the components, was in the lixivium after 7days of bioleaching. Among them, Ni, Zn and Al were bioleaching and entered into the lixivium with the form of ions. But the elemental Sn in the welding foot was oxidized to an ionic state into the lixivium through the action of A.f, then the Sn hydroxide precipitate was formed rapidly in the lixivium. After the first day of bioleaching, the concentration of Sn ion in the lixivium was decreased rapidly. Through single factor experiments by setting different leaching conditions, the results showed that when the initial pH of the medium was 1.0, the ratio of solid to liquid was 3:50, the inoculum(v/v) was 15%, the temperature was 30℃ and the rotating speed was 125r/min, A.f had the best effect on removing PCB surface components from the PCB. After 7days of bioleaching, the surface components of PCB were removed completely.