Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia.
Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia.
Waste Manag. 2018 Mar;73:556-565. doi: 10.1016/j.wasman.2017.01.001. Epub 2017 Jan 12.
High temperature pyrolysis investigations were carried out on waste printed circuit boards (PCBs) in the temperature range 800-1000°C under inert conditions, with an aim to determine optimal operating conditions for the recovery of copper. Pyrolysis residues were characterized using ICP-OES analysis, SEM/EDS and XRD investigations. Copper foils were successfully recovered after pyrolysis at 800°C for 10-20 min; the levels of Pb and Sn present were found to be quite low and these were generally present near the foil edges. The relative proportions of Pb and Sn became progressively higher at longer heating times due to enhanced diffusion of these molten metals in solid copper. While a similar behaviour was observed at 900°C, the pyrolysis at 1000°C resulted in copper forming Cu-Sn-Pb alloys; copper foils could no longer be recovered. Optimal conditions were identified for the direct recovery of copper from waste PCBs with minimal processing. This approach is expected to make significant contributions towards enhancing material recovery, process efficiency and the environmental sustainability of recycling e-waste. Pyrolysis at lower temperatures, short heating times, coupled with reductions in process steps are expected to significantly reduce energy consumption and pollution associated with the handling and processing of waste PCBs.
高温热解研究在惰性条件下对废印刷电路板（PCBs）进行，温度范围为 800-1000°C，目的是确定回收铜的最佳操作条件。使用 ICP-OES 分析、SEM/EDS 和 XRD 研究对热解残留物进行了表征。在 800°C 下进行 10-20 分钟的热解后，成功回收了铜箔；发现存在的 Pb 和 Sn 水平相当低，这些通常存在于箔片边缘附近。由于这些熔融金属在固体铜中的扩散增强，在较长的加热时间内，Pb 和 Sn 的相对比例逐渐升高。虽然在 900°C 时观察到类似的行为，但在 1000°C 的热解导致铜形成 Cu-Sn-Pb 合金；无法再回收铜箔。确定了从废 PCB 中直接回收铜的最佳条件，以实现最小的加工。这种方法有望为提高材料回收率、工艺效率和电子废物回收的环境可持续性做出重大贡献。预计低温热解、短加热时间以及减少工艺步骤将显著降低与废 PCB 处理和加工相关的能源消耗和污染。
