废电路板上电子元器件与基板加热-机械拆解过程中污染物的释放、转化与迁移机制

Waste printed circuit board (WPCB) with various components (capacitors, memory module etc.), containing various metals, possesses important recycling value. For the efficient recovery of these resources, we must first detach the electronic components from the laminate, then classify the electronic components accurately and recycle the metals according to the containing metals in components. Therefore, the disassembly of the electronic components from the WPCB laminate is the necessary step during the WPCB recycling process. Based on the research of heating-vibration dismantling process for electronic components and laminate from different types of WPCB materials, we will investigate the occurrence，concentrations and release characteristic of toxic substances contained in the laminate, electronic components and surface deposition dust. We will study the generation and migration mechanism of pollutants such as particulate matter (PM), volatile organic pollutants and semi-volatile organic pollutants (SVOPs) from WPCB materials to gas micro-environment, and discuss the effects of temperature, air and dismantling methods on the release of pollutants. Based on the PM analysis of concentration, morphology, size distribution and chemical composition, the gas-particulate partitioning mechanism of typical SVOPs in flue gas at different temperatures will be revealed. It will provide the basic research for the control removal of gas pollutants during WPCB heating-disassembly process, and the risk assessment in the process of electronic waste treatment.

废弃电路板（WPCB）带有多种元器件（电容器、内存条等），含有各种金属资源，具有重要回收价值。为了高效回收这些资源，首先必须使电子元器件与基板分离，根据含金属的种类进行精准分类，然后再生各种金属。因此，电路板上电子元器件与基板的拆解分离是WPCB资源化必要的环节。本研究在WPCB上元器件与基板加热-振动拆解工艺基础上，研究不同类型WPCB的基板材料、电子元器件、及表面沉积灰中毒害物质的赋存状态、组分浓度及加热释放特性，探讨颗粒物、挥发性有机物和半挥发性有机物（SVOPs）等气体污染物从WPCB材料到气体微环境的生成释放、迁移转化机制，并考察温度、气氛及拆解方式等因素对污染物释放的影响规律。在分析烟气颗粒物浓度、微观形貌、粒径分布及化学组成基础上，阐明烟气中典型SVOPs在不同温度条件下的气-粒分配规律。为加热拆解WPCB产生气体污染物的控制去除及电子垃圾处理过程中的风险评估提供基础研究。

含电子元器件的废电路板（WPCB）是电子垃圾中回收价值较高的拆解产物，项目采用加热模拟实验和自制装置对WPCB的热拆解进行了研究，重点关注拆解过程中排放烟气的污染特征，得到了如下一些结论：（1）对WPCB单一组件物料（基板材料、电容器外皮、防焊漆等）的热失重过程、热解产物进行了研究，溴化阻燃剂发生脱溴反应，板树脂热解主要产物为HBr和苯酚。电容器外皮热解产物检测出HCl、苯和甲苯等。利用模拟实验研究WPCB不同组分受热释放PBDEs的生成规律；（2）利用自制的空气加热-机械拆解装置进行WPCB的实际拆解实验，重点考察了不同加热温度条件下，排放烟气中颗粒物、重金属及多溴联苯醚（PBDEs）的排放水平、粒径分布及气粒分配规律。在100-260 oC范围内，加热拆解废电路板的气态和颗粒态∑39PBDEs排放因子范围分别为1.72~25.00 ng/g和4.44~649.08 ng/g。在100 oC和260 oC时的颗粒态PBDEs主要集中在 > 9.0 μm和0.7 ~ 1.1 μm颗粒物上，六溴、七溴等高溴代联苯醚的质量中位数空气动力学直径大于2.5 μm，而一溴至五溴等低溴代联苯醚主要分布在细颗粒中；（3）阐明4个电子垃圾处理车间（包括废电路板加热拆解车间）大气中PBDEs的气粒分配规律，并探讨了有机碳等因素对气粒分配的影响规律。研究结果为废电路板加热拆解等资源化过程的污染物排放与控制提供基础数据。