废电路板非金属物料资源化过程复合污染表征与作用机制研究

Generation of electronic waste (e-waste) has increased rapidly. While there are many types of electronic products and their compositions are complex, printed circuit boards (PCBs) scrape contained in each type of e-waste accounts for around 3% to 10% by weight. Generally, precious metals or substances can be successfully recovered via current technologies, the non-metallic fractions (NMFs), which take up almost 70 wt% of waste PCBs, have become problematic for the e-waste recycling industry. One of the most crucial points on the development of environmental-friendly and high added-value recycling technologies for NMFs scrap is the characterization and systematic evaluation of combined pollutions between heavy metals and flame-retardant pollutants from the recycling process. Therefore, this study is designed to focus on the NMFs. The typical recycling processes and recycled products have been chosen to quantify the residues and emissions of brominated flame retardants (BRFs), heavy metals and other pollutants, on this basis, to disclose the pollution level and their distribution associated with NMFs. Meanwhile, micro-scale materials flows and mass balances approaches have been employed to illustrate the environmental release of these pollutants. In addition, the interactive mechanisms and major impact factors of combined pollutions from the recycling processes have been investigated based on experimental study. Thus, effective approaches for the reduction and inhibition of pollutants can be put forward. The results are expected to be helpful for the environmentally sound management of NMFs and provide basic data for the promotion of NMFs recycling industry. Still, the fingdings has the potential to give insight into the solid waste contained combined pollutions, such as retardant plastics.

电子废物产生量逐年递增，尽管其产品类型和材料组成复杂多样，但其中均含有3%-10%不等的废旧电路板。基于现有各类技术可不同程度回收废电路板中的稀贵金属，而占到约70%的非金属物料(NMFs)，则成为电子废物回收处理的难题。影响NMFs清洁与高值资源化技术研发并进行应用的关键认知是对其中溴化阻燃剂类有机污染物-重金属复合型污染进行全面表征和系统评估。基于此，本课题将以NMFs为研究对象，针对其典型资源化过程及再生利用制品，分析重金属、溴化阻燃剂及其他有机污染物浓度含量，对其污染程度和分布特征进行综合研究；并基于创建的微尺度物质流和质量平衡系统分析模型，探明污染物的释放特征与强度；此外，通过模拟实验探究NMFs资源化过程复合污染交互作用及影响因素，并提出污染物抑制措施。研究结果可为NMFs的污染控制及环境友好技术研发提供基础数据，并为阻燃塑料等复合污染类废弃物研究提供资料佐证。

电子废物废旧电路板中约含70%的非金属物料(NMFs)，则成为电子废物回收处理的难题。本课题以NMFs为研究对象，针对其典型资源化过程及再生利用制品，分析重金属、溴化阻燃剂及其他有机污染物浓度含量，对其污染程度和分布特征进行综合研究；并基于创建的微尺度物质流和质量平衡系统分析模型，探明污染物的释放特征与强度；此外，通过模拟实验探究NMFs资源化过程复合污染交互作用及影响因素，结果表明仅2015年全国产生废旧电路板分离的非金属材料约20.1万吨（一倍方差6.7万吨），到2020年会增长到27.9万吨/年。非金属材料因产生源不同，其中所含重金属和溴化阻燃剂的浓度含量及其再资源化过程中的释放特征存在较大差异。例如，机械再生过程中存在PBDEs释放以及脱溴降解行为，其中冷却水中PBDEs浓度为1563.7ng/L，烟气中PBDEs浓度高达5203945.8-7755113.2 ng/m3。冷却水和烟气中排放因子分别为5484ng/kg和999157.6-1706124.9ng/kg。j进一步建立人体健康风险评估模型，对烟气和再生品造成的人体健康风险展开评估，结果显示，呼吸吸入是烟气暴露主要途径，暴露量为11.6-17.5mg/m3，致癌风险值均高于10-4，属于不可接受范围。研究结果可为NMFs的污染控制及环境友好技术研发提供基础数据，并为阻燃塑料等复合污染类废弃物研究提供资料佐证。