Life cycle assessment of the hydrometallurgical zinc production chain in China

Life cycle assessment was carried out via ReCiPe H method to evaluate environmental impact of the hydrometallurgical zinc production chain in China. National statistical data and process-based life cycle inventory (LCI) were used to build a zinc production LCI at the macro level. To confirm the credibility of this study, an uncertainty analysis was conducted via Monte-Carlo simulation. The impacts of climate change, human toxicity, marine ecotoxicity, freshwater ecotoxicity, metal depletion, and fossil depletion categories on the overall environmental burden were examined. The overall environmental burden was dominated by key processes, such as zinc ore mining and energy (i.e., electricity and natural gas) consumption. In 2013, the amounts of carbon dioxide, sulfur dioxide, nitrogen oxide, particulate matter, zinc, and copper generated by hydrometallurgical zinc production were 2.60 × 107, 4.29 × 104, 6.77 × 104, 1.23 × 104, 1.38 × 103, and 3.20 × 102 t. The first four substances accounted for 0.25%, 0.21%, 0.30%, and 0.10% of the overall national emission. Effective approaches to reduce the overall environmental impact of hydrometallurgical zinc production include improving the efficiencies of electricity, natural gas, and zinc ore consumption; substituting clean energy for coal-based electricity production; reducing the direct emission of zinc and copper; and increasing the national zinc recycle rate.