Environmental sustainability potentials of gold recovery via membrane distillation in the production of printed circuit boards

Material losses in hard-gold plating during rinsing are a costly aspect of printed circuit board (PCB) production and lead to environmental impacts from raw materials that do not end up in the final products. Previously, washing water containing gold was not directly reused in the same process at AT & S Austria Technologie & Systemtechnik AG. The implementation of a membrane distillation (MD) system now allows for the direct recovery of discharged valuables from processing water as a concentrate, facilitating its reintegration into the process and significantly reducing input materials. A life cycle assessment (LCA) evaluated impacts on climate change, terrestrial eutrophication, and resource use and showed a reduction of approximately 25% in the investigated impact categories. Additionally, a water footprint profile demonstrated the potential for water quality regarding acidification and aquatic eutrophication, as well as regional water scarcity. While water scarcity is reduced by 23%, water quality indicators have a reduction of up to over 47%. Overall, the MD system demonstrated potential savings of 23% to over 47%, contributing significantly to sustainability in PCB production through a closed-loop approach.