Environmental Impact Assessment of Hydrometallurgical Processes for Metal Recovery from WEEE Residues Using a Portable Prototype Plant

摘要

Life cycle assessment (LCA) was applied to hydrometallurgical treatments carried out using a new portable prototype plant for the recovery of valuable metals from waste electrical and electronic equipment (WEEE). The plant was fed with the WEEE residues from physical processes for the recycling of fluorescent lamps, cathode ray tubes (CRTs), Li-ion accumulators and printed circuit boards (PCBs). Leaching with sulfuric acid was carried out, followed by metal recovery by selective precipitation. A final step of wastewater treatment with lime was performed. The recovered metals included yttrium, zinc, cobalt, lithium, copper, gold, and silver. The category of global warming potential was the most critical one considering the specifications for southern European territories, with 13.3 kg CO_2/kg recovered metal from the powders/residues from fluorescent lamps, 19.2 kg CO_2/kg from CRTs, 27.0 kg CO_2/kg from Li-ion accumulators and 25.9 kg CO_2/kg from PCBs. Data also show that metal extraction steps have the highest load for the environment. In general, these processes appear beneficial for the environment in terms of CO_2 emissions, especially for metal recovery from WEEE residues from fluorescent lamps and CRTs.