Collaborative Research: Understanding and Optimizing A Supercritical Fluid Process for Recycling of Printed Circuit Boards

1133770（戴）。电子设备的广泛使用和产品寿命周期的缩短，使处理数量不断增加的过时电子设备成为一项具有挑战性的任务。每年产生的大量电子废物以及缺乏能够处理日益增加的电子废物的既定方法构成了严重的环境威胁。在成功回收电子设备所面临的挑战中，印刷电路板（PCB，每种电子产品的主要部件）的回收被认为是最困难的问题之一，因为PCB的结构和材料组成复杂。目前的PCB回收行业使用传统的冶金技术，其中纤维增强聚合物基质材料被焚烧。虽然传统的冶金技术在提高废旧电子产品的回收利用率方面做出了很大努力，但PCB回收行业仍然面临着环境效益差和经济效益有限的问题。 最近，在EAGER的资助下，该奖项的PI展示了在相对低/中等温度和压力下开发新型超临界流体（SCF）CO2基PCB回收工艺的概念验证初步工作。探索性实验表明，多氯联苯与金属分层，玻璃纤维保持其原始形态，因此不仅可以提高贵金属的回收率，还可以提高非金属材料的回收率。这一过程为多氯联苯的再循环开辟了一个新的领域，并提供了满足经济和环境要求的可能性。在目前的项目中，研究小组将系统地研究超临界流体工艺下PCB中键合材料的分层机制，并寻求理解结构/工艺关系。尽管文献记载了超临界流体在聚合物合成和加工中的应用，但是在揭示聚合物材料在超临界流体中的性能方面存在有限的现有工作。此外，研究小组将通过实施基于机理研究的工艺条件来优化SCF工艺，并系统地评估工艺性能。最后，该团队将对回收过程进行建模和验证，以便在成本、能源和环境影响方面扩大规模。 该团队将与工业合作者合作，促进基础研究向实际应用的转移。此外，研究和教育将贯穿整个项目期间。

1133770 (Dai). Widespread use of electronic equipment and shortening of product life cycles have created the challenging task of dealing with the ever-increasing quantity of obsolete electronic equipment. The huge amount of electronic waste (E-waste) generated each year and the lack of established methodologies capable of handling the increasing volumes of E-waste pose a severe environmental threat. Among the challenges to successful electronic equipment recycling, printed circuit board (PCB, primary components in every type of electronic product) recycling is recognized as one of the most difficult problems because of the complex construction and complicated materials composition of PCBs. The current PCB recycling industry uses traditional metallurgical technologies in which the fiber reinforced polymer matrix materials are incinerated. Although great effort has been made in the traditional metallurgical technologies for increasing the recycling efficiency for the end-of-life electronic products, the PCB recycling industry still faces the problems of poor environmental performance and limited economic returns. Recently, under an EAGER grant, the PIs of this award demonstrated proof-of-concept preliminary work for developing a novel supercritical fluid (SCF) CO2-based PCB recycling process at relatively low/medium temperatures and pressures. The exploratory experiments demonstrated that PCBs are delaminated with metals and glass fiber maintain their original form, making it possible to increase recovery rates not only for precious metals but also for non-metal materials. Such a process opens a new dimension for recycling of PCB and provides the possibility of satisfying economical and environmental demands. In the current project, the research team will systematically investigate the delamination mechanism of the bonding materials in PCBs under supercritical fluid processes and seek to understand structure/process relationships. Although literature documents the application of supercritical fluids in polymer synthesis and processing, there is limited existing work on revealing the performance of polymeric materials in supercritical fluids. In addition, the research team will optimize the SCF process by implementing process conditions based on the mechanism study and systematically evaluate process performance. Finally, the team will model and validate the recycling process for scale-up in terms of cost, energy, and environmental impact. The team will collaborate with industrial collaborators to promote transferring fundamental research to practical application. In addition, research and education will be integrated throughout the entire project duration.